Delivery of Oligonucleotides to the Liver with GalNAc: From Research to Registered Therapeutic Drug

Optimisation of Heated Electrospray Ionisation Parameters to Minimise In-Source Generated Impurities in the Analysis of Oligonucleotide Therapeutics

RATIONALE

Oligonucleotides have emerged as an important new class of therapeutic. Due to their structural complexity, this presents significant challenges for the development of analytical methods to characterise and determine their impurity profile. In this study, we introduce a sensitive ion-pair reverse phase method interfaced with mass spectrometry for analysis of antisense oligonucleotides and small interfering RNAs.

METHODS

Liquid chromatography-mass spectrometry analysis of antisense oligonucleotides and small interfering RNAs was performed using hexylamine: hexafluoro-2-propanol mobiles phases. LC-MS analysis was performed in both negative and positive ion mode. Electrospray ionisation source conditions including collision energy and temperature were optimised to minimise in-source generated impurities and alkylamine adducts in the analysis of oligonucleotide therapeutics.

RESULTS

The results show that under low or no in-source collision energy the presence of hexylamine adducts are observed and are predominantly on the lowest charge states present. As the in-source collision energy is increased, a reduction of hexylamine adducts is observed in conjunction with an increase in nucleobase loss in the gas phase, therefore generating in-source impurities. In comparison to tributylammonium acetate, increased MS sensitivity, higher charge states and effective removal of hexylamine adducts using mild source conditions was achieved.

CONCLUSIONS

Optimisation of the mild source conditions in conjunction with high pH mobile phases was combined with high-resolution accurate mass spectrometry analysis and automated deconvolution workflows to develop a simplified and streamlined approach for characterising oligonucleotide therapeutics and their related impurities.

A nasally administrated reactive oxygen species-responsive carrier-free gene delivery nanosystem for Alzheimer's disease combination therapy

Combination therapies targeting multiple pathways are needed in order to improve treatment outcomes in Alzheimer's disease (AD) due to its complex pathogenesis. Amyloid-β and microglia-mediated neuroinflammation significantly contribute to AD pathogenesis. Amyloid-β-related nucleic acid drugs have demonstrated considerable potential in AD treatment; however, their clinical translation is limited by complex synthesis processes and carrier toxicity. Herein, an intranasally administrated, reactive oxygen species (ROS)-responsive, carrier-free gene delivery nanosystem (FTBR-NAC) was constructed for re-polarizing microglia and decreasing amyloid-β expression. In this nanosystem, fingolimod was conjugated with biguanide via an ROS-responsive linker to form the carrier for β-secretase 1 siRNA (siBACE1) to form FTBR nanoparticles. The electropositivity of FTBR and mucolytic activity of N-acetylcysteine (NAC) together enhanced the brain entry of FTBR. Upon reaching the brain, FTBR responded to the elevated ROS at the pathological site, releasing siBACE1 and fingolimod. Administration of FTBR-NAC improved cognitive function in AD mice, demonstrating the high therapeutic efficacy of this relatively simple nanosystem.

GSH-Responsive GalNAc-Conjugated Glycopolymer for Targeted Survivin siRNA Delivery in Hepatocellular Carcinoma Therapy

Gene interference therapy has made significant progress in the treatment of various diseases by targeting specific pathogenic genes and down-regulating the production of harmful proteins. This approach enables the precise modulation of gene expression, offering potential therapeutic benefits for conditions driven by genetic mutations or abnormal protein accumulation. Survivin, an apoptosis-inhibiting protein, plays a critical role in regulating tumor cell proliferation and preventing programmed cell death. Its overexpression in liver cancer cells is strongly associated with poor prognosis and accelerated tumor progression. RNA interference (RNAi) therapy can effectively suppress the expression of Survivin in liver cancer, inhibiting tumor cell proliferation and promoting apoptosis. In this study, four distinct GalNAc-conjugated glycopolymer siRNA delivery systems were developed. By leveraging the efficient liver-targeting capability of the GalNAc moiety, Survivin-siRNA was specifically delivered to liver cancer cells through either covalent coupling or electrostatic adsorption. In vitro experiments demonstrated the excellent gene silencing effect of these siRNA complexes, highlighting their potential as a promising therapeutic strategy for liver cancer.

Receptor-ligand interactions for optimized endocytosis in targeted therapies

Receptor-mediated endocytosis plays a crucial role in the success of numerous therapies and remains central to advancing drug development. This process begins with ligand binding to specific receptors, triggering the internalization and intracellular trafficking of receptor-ligand complexes. These complexes are subsequently directed into distinct routes, either toward lysosomal degradation or recycling to the cell surface, with implications for therapeutic outcomes. This review examines receptor-ligand interactions as key modulators of endocytosis, emphasizing their role in shaping therapeutic design and efficacy. Advances in selecting receptor-ligand pairs and engineering ligands with optimized properties have enabled precise control over internalization, endosomal sorting, and trafficking, providing tailored solutions for diverse therapeutic applications. Leveraging these insights, strategies such as RNA-based therapies, antibody-drug conjugates (ADCs), and targeted protein degradation (TPD) platforms have been refined to selectively avoid or promote lysosomal degradation, thereby enhancing therapeutic efficacy. By bridging fundamental mechanisms of receptor-mediated endocytosis with innovative therapeutic approaches, this review offers a framework for advancing precision medicine.

Metabolic Stability and Targeted Delivery of Oligonucleotides: Advancing RNA Therapeutics Beyond The Liver

Oligonucleotides have emerged as a formidable new class of nucleic acid therapeutics. Fully modified oligonucleotides exhibit enhanced metabolic stability and display successful clinical applicability for targets formerly considered "undruggable". Accumulating studies show that conjugation to targeting modalities of stabilized oligonucleotides, especially small interfering RNAs (siRNAs), has enabled robust delivery to intended cells/tissues. However, the major challenge in the field has been the stability and targeted delivery of oligonucleotides (siRNAs and antisense oligonucleotides (ASOs)) to extrahepatic tissues. In this Perspective, we review chemistry innovations and emerging delivery approaches that have revolutionized oligonucleotide drug discovery and development. We explore findings from both academia and industry that highlight the potential of oligonucleotides for indications involving different extrahepatic organs─including skeletal muscles, brain, lungs, skin, heart, adipose tissue, and eyes. In all, continued advances in chemistry coupled with conjugation-based approaches or novel administration routes will further advance the delivery of oligonucleotides to extrahepatic tissues.

Trivalent siRNA-Conjugates with Guanosine as ASGPR-Binder Show Potent Knock-Down In Vivo

To increase the chemical space around the well-known GalNAc-ligand as ASGPR-binder, a high-throughput screening campaign was performed, testing approximately 550,000 compounds. After evaluation of the potential screening hits, only one compound, which showed high similarity with guanosine nucleosides, was chosen for further profiling. Crystal structure analysis revealed the coordination of the Ca2+-ion within the ASGPR-binding site by the cis-diol motif of the ribose unit as well as an additional π-π-interaction of the purine heterocycle to tryptophan-243. Based on these findings, guanosine was attached via the 5'-OH group to a recently described morpholino-based nucleotide using two different linker units. The resulting morpholino-guanosine building blocks were conjugated to the 5'-end of a literature-known transthyretin targeting small interfering RNA (siRNA), leading to trivalent siRNA-guanosine conjugates, which were tested for their TTR knockdown and exhibited similar potencies as the analogous GalNAc-conjugates in vitro and in vivo.

General Platform for Efficient and Modular Assembly of GalNAc-siRNA Conjugates via Primary Amines and o-Nitrobenzyl Alcohol Cyclization Photoclick Chemistry Enabling Rapid Access to Therapeutic Oligonucleotides

Oligonucleotide-based therapies, especially ligand-conjugated siRNAs, offer significant therapeutic potential for a wide array of diseases. However, conventional solid-phase synthesis and current postsynthetic in-solution conjugation methods face notable challenges related to efficiency, accessibility, and the scalability of diverse ligand-oligonucleotide conjugates. Herein, we introduce a novel strategy for highly efficient, rapid, and modular assembly of GalNAc-siRNA conjugates based on light-induced primary amine and o-nitrobenzyl alcohol cyclization (PANAC) chemistry. Leveraging the advantages of PANAC photoclick chemistry and modular conjugation linkers, our method enables the direct assembly of trivalent GalNAc (tGalNAc) with commercially available primary-amine-modified siRNAs. This approach demonstrates the efficient and rapid assembly of therapeutically relevant oligonucleotides with ligands of interest, offering operational simplicity and practicality; thus, it effectively overcomes the limitations of existing methods. More importantly, the developed siRNA-tGalNAc conjugates showed a robust gene silencing effect superior to the parent siRNA conjugate, highlighting the effectiveness of our method in generating and screening siRNA conjugates to enhance in vivo potency. Overall, our method enables modular and rapid assembly of therapeutically relevant oligonucleotide-tGalNAc conjugates using readily accessible oligonucleotides and commercially available tGalNAc-amine ligands. This approach expands the toolkit for generating ligand-oligonucleotide conjugates, providing a general and efficient platform with broad applicability, thereby advancing the optimization and development of oligonucleotide-based therapeutics.

Natural, modified and conjugated carbohydrates in nucleic acids

Storage of genetic information in DNA occurs through a unique ordering of canonical base pairs. However, this would not be possible in the absence of the sugar-phosphate backbone which is essential for duplex formation. While over a hundred nucleobase modifications have been identified (mainly in RNA), Nature is rather conservative when it comes to alterations at the level of the (deoxy)ribose sugar moiety. This trend is not reflected in synthetic analogues of nucleic acids where modifications of the sugar entity is commonplace to improve the properties of DNA and RNA. In this review article, we describe the main incentives behind sugar modifications in nucleic acids and we highlight recent progress in this field with a particular emphasis on therapeutic applications, the development of xeno-nucleic acids (XNAs), and on interrogating nucleic acid etiology. We also describe recent strategies to conjugate carbohydrates and oligosaccharides to oligonucleotides since this represents a particularly powerful strategy to improve the therapeutic index of oligonucleotide drugs. The advent of glycoRNAs combined with progress in nucleic acid and carbohydrate chemistry, protein engineering, and delivery methods will undoubtedly yield more potent sugar-modified nucleic acids for therapeutic, biotechnological, and synthetic biology applications.

Landscape of small nucleic acid therapeutics: moving from the bench to the clinic as next-generation medicines

The ability of small nucleic acids to modulate gene expression via a range of processes has been widely explored. Compared with conventional treatments, small nucleic acid therapeutics have the potential to achieve long-lasting or even curative effects via gene editing. As a result of recent technological advances, efficient small nucleic acid delivery for therapeutic and biomedical applications has been achieved, accelerating their clinical translation. Here, we review the increasing number of small nucleic acid therapeutic classes and the most common chemical modifications and delivery platforms. We also discuss the key advances in the design, development and therapeutic application of each delivery platform. Furthermore, this review presents comprehensive profiles of currently approved small nucleic acid drugs, including 11 antisense oligonucleotides (ASOs), 2 aptamers and 6 siRNA drugs, summarizing their modifications, disease-specific mechanisms of action and delivery strategies. Other candidates whose clinical trial status has been recorded and updated are also discussed. We also consider strategic issues such as important safety considerations, novel vectors and hurdles for translating academic breakthroughs to the clinic. Small nucleic acid therapeutics have produced favorable results in clinical trials and have the potential to address previously "undruggable" targets, suggesting that they could be useful for guiding the development of additional clinical candidates.

Emerging, novel gene-modulating therapies for transthyretin amyloid cardiomyopathy

Transthyretin amyloid cardiomyopathy (ATTR-CM) is a progressive, life-threatening disease caused by the pathological deposition of misfolded transthyretin (TTR) protein in the myocardium, leading to restrictive cardiomyopathy and heart failure. While TTR stabilizers such as tafamidis and acoramidis are the only FDA-approved treatments, novel gene-modulating therapies are emerging as transformative approaches. Small interfering RNA (siRNA) and antisense oligonucleotide (ASO) therapies effectively reduce TTR production and have demonstrated promising clinical outcomes, though their use in cardiac amyloidosis remains investigational. CRISPR-Cas9 therapies represent a paradigm shift, offering a potential one-time treatment by permanently silencing the TTR gene. Recent clinical trials have shown significant TTR reduction and stabilization of disease biomarkers, although long-term safety and efficacy require further evaluation. Despite the lack of direct comparisons among these modalities, their emergence highlights a promising future for ATTR-CM management. This review discusses the pathogenesis of ATTR-CM, mechanisms of novel gene-modulating therapies, clinical evidence, challenges, and the future outlook for advancing treatment options.

Nano Approaches to Nucleic Acid Delivery: Barriers, Solutions, and Current Landscape

Nucleic acid (NA) therapy holds tremendous potential for treating a wide range of genetic diseases by the delivery of therapeutic genes into target cells. However, significant challenges exist in safely and effectively delivering these genes to their intended locations. Viral vectors, though efficient, pose risks such as immunogenicity and mutagenesis. This has resulted in growing interest in non-viral, nanoparticle-based NA delivery systems. This review article describes various physiological barriers to NA delivery and explores nanoparticle-based NA delivery systems, including bioengineered nanoparticles, peptides, lipid nanoparticles, and polymeric nanoparticles, highlighting their unique features to overcome in vivo barriers for NA delivery. While these nanoparticle-based NA delivery systems offer a promising alternative to viral vectors, challenges related to cytotoxicity, reproducible synthesis, and cost need to be addressed. The current clinical landscape of NA delivery is also discussed, emphasizing the need for safer, scalable, and cost-effective solutions. Nanoparticles represent a promising future in NA therapy, with the possibility of developing clinically relevant, non-toxic, stable, and non-immunogenic delivery vehicles, paving the way for broader therapeutic applications and improved clinical outcomes.

Liver ALKBH5 regulates glucose and lipid homeostasis independently through GCGR and mTORC1 signaling

Maintaining glucose and lipid homeostasis is crucial for health, with dysregulation leading to metabolic diseases such as type 2 diabetes mellitus (T2DM) and metabolic dysfunction-associated fatty liver disease (MAFLD). This study identifies alkylation repair homolog protein 5 (ALKBH5), an RNA N6-methyladenosine (m6A) demethylase, as a major regulator in metabolic disease. ALKBH5 is up-regulated in the liver during obesity and also phosphorylated by protein kinase A, causing its translocation to the cytosol. Hepatocyte-specific deletion of Alkbh5 reduces glucose and lipids by inhibiting the glucagon receptor (GCGR) and mammalian target of rapamycin complex 1 (mTORC1) signaling pathways. Targeted knockdown of hepatic Alkbh5 reverses T2DM and MAFLD in diabetic mice, highlighting its therapeutic potential. This study unveils a regulatory mechanism wherein ALKBH5 orchestrates glucose and lipid homeostasis by integrating the GCGR and mTORC1 pathways, providing insight into the regulation of metabolic diseases.

Expanding Conjugate Space of RNAi Therapeutics: Ligand at the 3' End of the Antisense Strand Achieves Uncompromised In Vivo Potency and Efficacy and Reveals Interactions with the Argonaute-2 PAZ Domain

The conjugation of the sense strands of small interfering RNA (siRNA) to tri-N-acetylgalactosamine (GalNAc), the ligand for a hepatocyte-specific receptor, enables the delivery of multiple clinically approved therapeutic agents that act through the RNA interference pathway. Here, we report the systematic evaluation of siRNAs with the 3' termini of antisense strands conjugated to GalNAc for the first time. These designs retained the same receptor affinity, in vitro and in vivo activities, as well as the same level of loading into the RNA-induced silencing complex as siRNAs with a GalNAc-conjugated sense strand. A siRNA with a GalNAc-conjugated antisense strand of 22 nucleotides had better activity than a siRNA with a 23-nucleotide antisense strand. Computational modeling of a complex of a GalNAc-conjugated antisense strand with the PAZ domain of Ago2 rationalizes the importance of the interaction of phosphate at the 3' terminus with the PAZ domain to explain the observed activity of these siRNAs.

Effect of pH-Responsive Ligands on mRNA Knockdown in EGFR-Targeting Ligand-Conjugated siRNAs

Ligand-conjugated small interfering RNAs (siRNAs) have emerged as a powerful approach to developing nucleic acid-based medicines. To achieve efficient mRNA knockdown, it is important to select targeting receptors with high expression and ligands that exhibit rapid internalization. However, the key characteristics of ligand-receptor sets involved in the postinternalization process remain largely unclear. In this study, we investigated the effect of ligand-receptor binding dissociation under low pH conditions, known as a postendocytic environment. Specifically, we chemically synthesized several modified epidermal growth factor (EGF) ligands that showed a variety of binding activities to the EGF receptor (EGFR) at low pH. Among these modified ligands, the siRNA conjugate with chemically synthesized EGF H10Y/H16Y, which is a less pH-responsive variant, exhibited reduced internalization and mRNA knockdown activity at high concentrations in EGFR-expressing cells. Additionally, we explored the use of antibody-related molecules (anti-EGFR IgG and Fab) as targeting moieties for siRNA conjugates. The anti-EGFR Fab-siRNA, which showed dissociation of EGF under low pH conditions, demonstrated stronger internalization and mRNA knockdown activity compared to the anti-EGFR IgG-siRNA, which strongly binds EGF at low pH. These data emphasize the importance of intracellular ligand-receptor dissociation and provide insights for future advancements in the field.

Hepatocyte targeting via the asialoglycoprotein receptor

This review highlights the potential of asialoglycoprotein receptor (ASGPR)-mediated targeting in advancing liver-specific treatments and underscores the ongoing progress in the field. First, we provide a comprehensive examination of the nature of ASGPR ligands, both natural and synthetic. Next, we explore various drug delivery strategies leveraging ASGPR, with a particular emphasis on the delivery of therapeutic nucleic acids such as small interfering RNAs (siRNAs) and antisense oligonucleotides (ASOs). An in-depth analysis of the current status of RNA interference (RNAi) and ASO-based therapeutics is included, detailing approved therapies and those in various stages of clinical development (phases 1 to 3). Afterwards, we give an overview of other ASGPR-targeted conjugates, such as those with peptide nucleic acids or aptamers. Finally, targeted protein degradation of extracellular proteins through ASGPR is briefly discussed.

RNA editing in disease: mechanisms and therapeutic potential

Adenosine to inosine conversion by adenosine deaminases acting on RNA (ADARs) was first identified in the late 1980s of the previous century. As the conversion of adenosines to inosines can be easily detected by sequencing of cDNAs, where the presence of an inosine reads out as a guanosine, the analysis of this type of RNA editing has become widespread. Consequently, several pipelines for detecting inosines in transcriptomes have become available. Still, how to interpret the consequences and alterations of RNA-editing events in whole transciptome editomes is a matter of debate. In particular, the cause or consequence of altered editomes on disease development is poorly understood. Similarly, absolute frequencies of editing events in single molecules, their longitudinal distribution, and naturally occurring changes during development, in different tissues, or in response to physiological changes need to be explored. Lastly, while the use of site-directed RNA editing as a treatment of certain genetic diseases is rapidly evolving, the applicability of this technology still faces several technical obstacles. In this review, we describe the current state of knowledge on adenosine deamination-type RNA editing, its involvement in disease development, and its potential as a therapeutic. Lastly, we highlight open challenges and questions that need to be addressed.

Developing splice-switching oligonucleotides for urea cycle disorder using an integrated diagnostic and therapeutic platform

BACKGROUNDS & AIMS

Citrin deficiency (CD) is an autosomal recessive urea cycle disorder caused by biallelic loss-of-function variants in the SLC25A13 gene, leading to life-threatening hyperammonemia and hypoglycemia. Variants in deep introns can cause genetic diseases by altering splicing and are often missed by current diagnostic tools. Splice-switching oligonucleotides (SSOs) can resolve certain intronic variants, but patients harboring such variants need to be identified. We present a lean workflow from molecular diagnostics to SSO development to resolve splice-altering variants in deep introns that is applicable to other genetic disorders.

METHODS

A deep intronic-gene panel was designed to identify deep intronic variants. SSOs were then developed and validated in vitro using a minigene assay and induced hepatocytes, and target engagement was verified in vivo by hydrodynamic tail vein injection of minigenes and SSOs.

RESULTS

With the deep intronic-gene panel and RNA analysis, we identified a novel SLC25A13 c.469-2922G>T variant that promotes the inclusion of a premature stop codon-containing pseudo-exon, SLC25A13-PE5, thereby causing CD. By a stepwise rational SSO design approach, we identified potent candidates inhibiting SLC25A13-PE5 at EC50 <2 nM in vitro. Upon conjugating the SSOs with GalNAc (N-acetylgalactosamine), they were validated to rescue normal protein expression and restore ureagenesis and ammonia clearance, key urea cycle functions, in patient-derived induced hepatocytes. In vivo on-target efficacy of the clinical GalNAc-SSO candidate, in the absence of acute toxicity and inflammation, was observed in a mouse model with exogenous hepatic minigene expression.

CONCLUSIONS

Our data validates a platform to redefine the molecular diagnosis of urea cycle disorders and provides proof-of-concept for a precision therapy for patients with CD, for whom the only effective treatment is liver transplantation.

IMPACT AND IMPLICATIONS

Deep intronic variants are common causes of genetic diseases that are commonly neglected. In this study, we demonstrate an integrated precision diagnostic and therapeutic approach for urea cycle disorders. Specifically, we focus on citrin deficiency, going from the discovery of a novel splice variant in the SLC25A13 gene with our novel deep intronic-gene panel for urea cycle disorders, to the development and in vivo validation of an efficacious splice-switching oligonucleotide candidate for the pathogenic splice variant. We envision the possibility of extrapolating this pipeline to the diagnosis and development of treatments for other rare genetic diseases.

GalNAc-Conjugated siRNA Targeting Complement C3 Inhibits Osteoclast Activation in Periodontitis

OBJECTIVE

The complement cascade plays an important role in the inflammation amplification and tissue destruction of periodontitis. Importantly, complement C3 was proved to be the central element of complement cascade. Thus, targeting inhibition of C3 has become one of the focuses of treatment method development and exploration.

METHODS

The siRNAs targeting C3 were designed and screened for in vitro potency. The selected siRNA was conjugated to GalNAc (GalNAc-C3 siRNA) for liver-specific delivery. The mouse model of periodontitis was established by silk ligation. Stereomicroscopy, Micro-CT, histological and histochemical assessment, and immunofluorescence staining were performed to evaluate the level of bone destructive and osteoclast activity. The influence of GalNAc-C3 siRNA on inflammatory reactions was determined by qRT-PCR, ELISA, and flow cytometry.

RESULTS

GalNAc-C3 siRNA showed great in vivo potency and durability to silence hepatic C3 mRNA expression. GalNAc-C3 siRNA treatment could effectively inhibit the production of inflammatory cytokines (IL-17A, TNF-α, IL-6, and IFN-γ) and restrain Th17 differentiation. Importantly, the expression of RANKL and differentiation of osteoclast were inhibited by GalNAc-C3 siRNA.

CONCLUSION

GalNAc-C3 siRNA could efficiently play a role in bone protection by inhibiting inflammatory responses and osteoclast activities. This therapeutic siRNA may become an effective treatment strategy for periodontitis.

Designed endocytosis-inducing proteins degrade targets and amplify signals

Endocytosis and lysosomal trafficking of cell surface receptors can be triggered by endogenous ligands. Therapeutic approaches such as lysosome-targeting chimaeras1,2 (LYTACs) and cytokine receptor-targeting chimeras3 (KineTACs) have used this to target specific proteins for degradation by fusing modified native ligands to target binding proteins. Although powerful, these approaches can be limited by competition with native ligands and requirements for chemical modification that limit genetic encodability and can complicate manufacturing, and, more generally, there may be no native ligands that stimulate endocytosis through a given receptor. Here we describe computational design approaches for endocytosis-triggering binding proteins (EndoTags) that overcome these challenges. We present EndoTags for insulin-like growth factor 2 receptor (IGF2R) and asialoglycoprotein receptor (ASGPR), sortilin and transferrin receptors, and show that fusing these tags to soluble or transmembrane target protein binders leads to lysosomal trafficking and target degradation. As these receptors have different tissue distributions, the different EndoTags could enable targeting of degradation to different tissues. EndoTag fusion to a PD-L1 antibody considerably increases efficacy in a mouse tumour model compared to antibody alone. The modularity and genetic encodability of EndoTags enables AND gate control for higher-specificity targeted degradation, and the localized secretion of degraders from engineered cells. By promoting endocytosis, EndoTag fusion increases signalling through an engineered ligand-receptor system by nearly 100-fold. EndoTags have considerable therapeutic potential as targeted degradation inducers, signalling activators for endocytosis-dependent pathways, and cellular uptake inducers for targeted antibody-drug and antibody-RNA conjugates.

Nanobody-Oligonucleotide Conjugates (NucleoBodies): The Next Frontier in Oligonucleotide Therapy

As of now, more than 15 oligonucleotide drugs, primarily small interfering RNAs and antisense oligonucleotide classes, have been approved by the US FDA for therapeutic use, and many more are under clinical trials. However, safe and effective delivery of the oligonucleotide-based drugs to the target tissue still remains a major challenge. For enhanced plasma half-life, effective endosomal release, and other multiple functionalities, various carrier molecules have been used over the years. The successful therapeutic application of antibody-drug conjugates has made antibodies a popular choice for the delivery of oligonucleotide payloads into the target tissues. Single-chain variable domains of heavy chain antibodies (nanobodies) have proven a promising alternative to antibodies in recent years due to their small size, high affinity for the target, cell-penetrating potency, simple and easy production. The present review highlights the oligonucleotide drug types and their conjugation with nanobodies called NucleoBodies for effective targeted delivery, detection and diagnostics.

Protein Arginine Methyltransferase 1: A Multi-Purpose Player in the Development of Cancer and Metabolic Disease

Protein arginine methyltransferase 1 (PRMT1) is the main PRMT family member involved in the formation of monomethylarginine and asymmetric dimethylarginine on its protein substrates. Many protein substrates of PRMT1 are key mediators of cell proliferation and oncogenesis. As such, the function of PRMT1 has been most prominently investigated in the context of cancer development. However, recent in vitro and in vivo studies have highlighted that PRMT1 may also promote metabolic disorders. With the current review, we aim to present an in-depth overview of how PRMT1 influences epigenetic modulation, transcriptional regulation, DNA damage repair, and signal transduction in cancer. Furthermore, we summarize the current knowledge regarding the role of PRMT1 in metabolic reprogramming, lipid metabolism, and glucose metabolism and describe the association of PRMT1 with numerous metabolic pathologies such as obesity, liver disease, and type 2 diabetes. It has become apparent that inhibiting the function of PRMT1 will likely serve as the most beneficial therapeutic approach, since several PRMT1 inhibitors have already been shown to exert positive effects on both cancer and metabolic disease in preclinical settings. However, pharmacological PRMT1 inhibition has not yet been shown to be therapeutically effective in clinical studies.

FORCE platform overcomes barriers of oligonucleotide delivery to muscle and corrects myotonic dystrophy features in preclinical models

BACKGROUND

We developed the FORCETM platform to overcome limitations of oligonucleotide delivery to muscle and enable their applicability to neuromuscular disorders. The platform consists of an antigen-binding fragment, highly specific for the human transferrin receptor 1 (TfR1), conjugated to an oligonucleotide via a cleavable valine-citrulline linker. Myotonic dystrophy type 1 (DM1) is a neuromuscular disorder caused by expanded CUG triplets in the DMPK RNA, which sequester splicing proteins in the nucleus, lead to spliceopathy, and drive disease progression.

METHODS

Multiple surrogate conjugates were generated to characterize the FORCE platform. DYNE-101 is the conjugate designed to target DMPK and correct spliceopathy for the treatment of DM1. HSALR and TfR1hu/mu;DMSXLTg/Tg mice were used as models of myotonic dystrophy, the latter expresses human TfR1 and a human DMPK RNA with >1,000 CUG repeats. Cynomolgus monkeys were used to determine translatability of DYNE-101 pharmacology to higher species.

RESULTS

In HSALR mice, a surrogate FORCE conjugate achieves durable correction of spliceopathy and improves myotonia to a greater extent than unconjugated ASO. In patient-derived myoblasts, DYNE-101 reduces DMPK RNA and nuclear foci, consequently improving spliceopathy. In TfR1hu/mu;DMSXLTg/Tg mice, DYNE-101 reduces mutant DMPK RNA in muscle, thereby correcting splicing. Reduction of DMPK foci in cardiomyocyte nuclei accompanies these effects. Low monthly dosing of DYNE-101 in TfR1hu/mu;DMSXLWT/Tg mice or cynomolgus monkeys leads to a profound reduction of DMPK expression in muscle.

CONCLUSIONS

These data validate FORCE as a drug delivery platform and support the notion that DM1 may be treatable with low and infrequent dosing of DYNE-101.

The Emergence of Oligonucleotide Building Blocks in the Multispecific Proximity-Inducing Drug Toolbox of Destruction

Oligonucleotides are a rapidly emerging class of therapeutics. Their most well-known examples are informational drugs that modify gene expression by binding mRNA. Despite inducing proximity between biological machinery and mRNA when applied to modulating gene expression, oligonucleotides are not typically labeled as "proximity-inducing" in literature. Yet, they have recently been explored as building blocks for multispecific proximity-inducing drugs (MPIDs). MPIDs are unique because they can direct endogenous biological machinery to destroy targeted molecules and cells, in contrast to traditional drugs that inhibit only their functions. The unique mechanism of action of MPIDs has enabled the targeting of previously "undruggable" molecular entities that cannot be effectively inhibited. However, the development of MPIDs must ensure that these molecules will selectively direct a potent, destruction-based mechanism of action toward intended targets over healthy tissues to avoid causing life-threatening toxicities. Oligonucleotides have emerged as promising building blocks for the design of MPIDs because they are sequence-controlled molecules that can be rationally designed to program multispecific binding interactions. In this Review, we examine the emergence of oligonucleotide-containing MPIDs in the proximity induction space, which has been dominated by antibody and small molecule MPID modalities. Moreover, examples of oligonucleotides developed as MPID candidates in immunotherapy and protein degradation are discussed to demonstrate the utility of oligonucleotides in expanding the scope and selectivity of the MPID toolbox. Finally, we discuss the utility of programming "AND" gates into oligonucleotide scaffolds to encode conditional responses that have the potential to be incorporated into MPIDs, which can further enhance their selectivity, thus increasing the scope of this drug category.

Design and Synthesis of Dual Galectin-3 and EGFR Inhibitors Against Liver Fibrosis

Liver fibrosis, mainly arising from chronic viral or metabolic liver diseases, is a significant global health concern. There is currently only one FDA-approved drug (Resmetirom) in the market to combat liver fibrosis. Both galectin-3 and epidermal growth factor receptor (EGFR) play important roles in liver fibrosis, while galectin-3 may interact with EGFR. Galectin-3 inhibitors, typically lactose or galactose derivatives may inhibit liver fibrosis. We hypothesized that targeting both galectin-3 and EGFR may have better effect against liver fibrosis. Here, EGFR inhibitor erlotinib was used in a series of designed galectin-3 inhibitors after hybridization with the pharmacophore structure in reported galectin-3 inhibitors to impede hepatic stellate cells (HSCs) activation by a typical method of click chemistry. Bioactivity test results showed that compound 29 suppressed TGF-β-induced upregulation of fibrotic markers (α-SMA, fibronectin-1, and collagen I). The preferred compound 29 displayed better binding to galectin-3 (KD=52.29 μM) and EGFR protein (KD=3.31 μM) by SPR assay. Further docking studies were performed to clarify the possible binding mode of compound 29 with galectin-3 and EGFR. Taken together, these results suggested that compound 29 could be a potential dual galectin-3 and EGFR inhibitor as leading compound for anti-liver fibrosis new drug development.

Design and Preliminary Screen of Antisense Oligonucleotides

Antisense Oligonucleotides (ASOs) are short, synthetic oligonucleotides that specifically bind to target RNA sequences to modulate their expression. ASOs have applications in both research and clinical therapy, with more than eight FDA-approved products and numerous others in clinical development. The functionality of ASOs is determined by their nucleotide sequence and the chemical modifications they carry. These modifications can define the ASO's function, and increase its stability, safety, and distribution in the body. In this chapter, we offer a comprehensive guide to designing RNAse-H1 recruiting ASOs, including guideline for sequence selection and chemical modifications. Additionally, we will outline a protocol for initial screenings of ASO libraries, providing recommendations for selection of the suitable screening platform.

Prevent and Reverse Metabolic Dysfunction-Associated Steatohepatitis and Hepatic Fibrosis via mRNA-Mediated Liver-Specific Antibody Therapy

Chronic exposure of the liver to multiple insults culminates in the development of metabolic dysfunction-associated steatohepatitis (MASH), a complicated metabolic syndrome characterized by hepatic steatosis and inflammation, typically accompanied by progressive fibrosis. Despite extensive clinical evaluation, there remain challenges in MASH drug development, which are primarily due to unsatisfactory efficacy and limited specificity. Strategies to address the unmet medical need for MASH with fibrosis before it reaches the irreversible stage of decompensated cirrhosis are critically needed. Herein, we developed an mRNA-mediated liver-specific antibody therapy for MASH and hepatic fibrosis using a targeted lipid nanoparticle (LNP) delivery system. When encapsulated with IL-11 single-chain variable fragment (scFv)-encoded mRNA, the targeted AA3G LNP (termed mIL11-scFv@AA3G) specifically accumulated in the liver and secreted IL-11 scFv to neutralize overexpressed IL-11 in hepatic environments, thus inhibiting the IL-11 signaling pathway in hepatocytes and hepatic stellate cells. As a preventative regimen, systemic administration of mIL11-scFv@AA3G reversed MASH and prevented the progression to fibrosis in a murine model of early MASH. Notably, mIL11-scFv@AA3G exhibited superior efficacy compared to systemic administration of IL-11 scFv alone, attributed to the sustained antibody expression in the liver, which lasted 18-fold longer than that of IL-11 scFv. When tested in the MASH model with fibrosis, mIL11-scFv@AA3G effectively ameliorated steatosis and resolved fibrosis and inflammation. These findings present a versatile LNP platform targeting liver cell subtypes for the sustained expression of therapeutic antibodies to treat MASH and fibrosis. The developed mRNA-mediated liver-specific antibody therapy offers a promising approach for addressing MASH and holds the potential for expansion to various other diseases.

A Novel Pot-Economy Approach to the Synthesis of Triantennary GalNAc-Oligonucleotide

N-Acetylgalactosamine (GalNAc) is an efficient and multifunctional delivery tool in the development and synthesis of chemically modified oligonucleotide therapeutics (conjugates). Such therapeutics demonstrate improved potency in vivo due to the selective and efficient delivery to hepatocytes in the liver via receptor-mediated endocytosis, which is what drives the high interest in this molecule. The ways to synthesize such structures are relatively new and have not been optimized in terms of the yields and stages both in lab and large-scale synthesis. Another significant criterion, especially in large-scale synthesis, is to match ecological norms and perform the synthesis in accordance with the Green Chemistry approach, i.e., to control and minimize the amounts of reagents and resources consumed and the waste generated. Here, we provide a robust and resource effective pot-economy method for the synthesis of triantennary GalNAc and GalNAc phosphoramidite/CPG optimized for laboratory scales.

Novel NTCP ligand dimeric bile acid conjugated with ASO reduce hepatitis B virus surface antigen in vivo

Hepatitis B virus (HBV) specifically infects hepatocytes and causes severe liver diseases. However, functional cure is rarely attainable by current treatment modalities. Anti-sense oligonucleotide (ASO), which targets pregenomic RNAs to reduce hepatitis B virus (HBV) antigen production and viral replication, has been studied as a novel treatment strategy for HBV cure and can be conjugated with N-acetylgalactosamine (GalNAc), thereby enhancing hepatocyte uptake via the asialoglycoprotein receptor (ASGPR). In comparison to GalNAc-ASO conjugation, clinical research indicates that unconjugated ASO is more effective in reducing hepatitis B virus surface antigen level. Recent studies have revealed that human sodium taurocholate co-transporting polypeptide (NTCP) is a functional cellular receptor for hepatitis B virus (HBV), and the bivalent bile acid structure may interact with multiple binding sites on NTCP, yielding much stronger interaction and substantially improved binding affinity. In this study, we synthesized NTCP ligand-antisense oligonucleotide (ASO) conjugation and evaluated the potential of antiviral therapy specifically reduction of HBV antigenemia in mice in vivo.

Xalnesiran with or without an Immunomodulator in Chronic Hepatitis B

BACKGROUND

Xalnesiran, a small interfering RNA molecule that targets a conserved region of the hepatitis B virus (HBV) genome and silences multiple HBV transcripts, may have efficacy, with or without an immunomodulator, in patients with chronic HBV infection.

METHODS

We conducted a phase 2, multicenter, randomized, controlled, adaptive, open-label platform trial that included the evaluation of 48 weeks of treatment with xalnesiran at a dose of 100 mg (group 1), xalnesiran at a dose of 200 mg (group 2), xalnesiran at a dose of 200 mg plus 150 mg of ruzotolimod (group 3), xalnesiran at a dose of 200 mg plus 180 μg of pegylated interferon alfa-2a (group 4), or a nucleoside or nucleotide analogue (NA) alone (group 5) in participants with chronic HBV infection who had virologic suppression with NA therapy. The primary efficacy end point was hepatitis B surface antigen (HBsAg) loss (HBsAg level, <0.05 IU per milliliter) at 24 weeks after the end of treatment. Safety was also assessed.

RESULTS

Among 159 participants (30, 30, 34, 30, and 35 in groups 1 through 5, respectively), the primary end-point event occurred in 7% (95% confidence interval [CI], 1 to 22) of those in group 1, in 3% (95% CI, 0 to 17) of those in group 2, in 12% (95% CI, 3 to 28) of those in group 3, in 23% (95% CI, 10 to 42) of those in group 4, and in none (95% CI, 0 to 10) of those in group 5. In groups 1 through 5, respectively, HBsAg seroconversion occurred in 3%, none, 3%, 20%, and none of the participants at 24 weeks after the end of treatment. HBsAg loss with or without seroconversion occurred only in participants with a screening HBsAg level below 1000 IU per milliliter. In groups 1 through 5, respectively, grade 3 or 4 adverse events occurred in 17%, 10%, 18%, 50%, and 6% of the participants, with the most frequent event being an elevated alanine aminotransferase level.

CONCLUSIONS

Among participants with chronic HBV infection who had virologic suppression with NA therapy, treatment with xalnesiran plus an immunomodulator resulted in HBsAg loss at 24 weeks after the end of treatment in a substantial percentage of participants. Grade 3 or 4 adverse events were not uncommon. (Funded by F. Hoffmann-La Roche; Piranga ClinicalTrials.gov number, NCT04225715.).

Advanced siRNA delivery in combating hepatitis B virus: mechanistic insights and recent updates

Hepatitis B virus (HBV) infection is a major health problem, causing thousands of deaths each year worldwide. Although current medications can often inhibit viral replication and reduce the risk of liver carcinoma, several obstacles still hinder their effectiveness. These include viral resistance, prolonged treatment duration, and low efficacy in clearing viral antigens. To address these challenges in current HBV treatment, numerous approaches have been developed with remarkable success. Among these strategies, small-interfering RNA (siRNA) stands out as one of the most promising therapies for hepatitis B. However, naked siRNAs are vulnerable to enzymatic digestion, easily eliminated by renal filtration, and unable to cross the cell membrane due to their large, anionic structure. Therefore, effective delivery systems are required to protect siRNAs and maintain their functionality. In this review, we have discussed the promises of siRNA therapy in treating HBV, milestones in their delivery systems, and products that have entered clinical trials. Finally, we have outlined the future perspectives of siRNA-based therapy for HBV treatment.

Nucleic acid drugs: recent progress and future perspectives

High efficacy, selectivity and cellular targeting of therapeutic agents has been an active area of investigation for decades. Currently, most clinically approved therapeutics are small molecules or protein/antibody biologics. Targeted action of small molecule drugs remains a challenge in medicine. In addition, many diseases are considered 'undruggable' using standard biomacromolecules. Many of these challenges however, can be addressed using nucleic therapeutics. Nucleic acid drugs (NADs) are a new generation of gene-editing modalities characterized by their high efficiency and rapid development, which have become an active research topic in new drug development field. However, many factors, including their low stability, short half-life, high immunogenicity, tissue targeting, cellular uptake, and endosomal escape, hamper the delivery and clinical application of NADs. Scientists have used chemical modification techniques to improve the physicochemical properties of NADs. In contrast, modified NADs typically require carriers to enter target cells and reach specific intracellular locations. Multiple delivery approaches have been developed to effectively improve intracellular delivery and the in vivo bioavailability of NADs. Several NADs have entered the clinical trial recently, and some have been approved for therapeutic use in different fields. This review summarizes NADs development and evolution and introduces NADs classifications and general delivery strategies, highlighting their success in clinical applications. Additionally, this review discusses the limitations and potential future applications of NADs as gene therapy candidates.

Recent Advances in miRNA-Based Therapy for MASLD/MASH and MASH-Associated HCC

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), is a growing health concern worldwide, affecting more than 1 billion adults. It may progress to metabolic dysfunction-associated steatohepatitis (MASH), cirrhosis, and ultimately hepatocellular carcinoma (HCC). Emerging evidence has demonstrated the role in this transition of microRNAs (miRNAs), which regulate the expression of genes associated with lipid metabolism, inflammation, fibrosis, and cell proliferation. Specific miRNAs have been identified to exacerbate or mitigate fibrotic and carcinogenic processes in hepatic cells. The modulation of these miRNAs through synthetic mimics or inhibitors represents a promising therapeutic strategy. Preclinical models have demonstrated that miRNA-based therapies can attenuate liver inflammation, reduce fibrosis, and inhibit tumorigenesis, thus delaying or preventing the onset of HCC. However, challenges such as delivery mechanisms, off-target effects, and long-term safety remain to be addressed. This review, focusing on recently published preclinical and clinical studies, explores the pharmacological potential of miRNA-based interventions to prevent MASLD/MASH and progression toward HCC.

Mammalian cell-based production of glycans, glycopeptides and glycomodules

Access to defined glycans and glycoconjugates is pivotal for discovery, dissection, and harnessing of a range of biological functions orchestrated by cellular glycosylation processes and the glycome. We previously employed genetic glycoengineering by nuclease-based gene editing to develop sustainable production of designer glycoprotein therapeutics and cell-based glycan arrays that display glycans in their natural context at the cell surface. However, access to human glycans in formats and quantities that allow structural studies of molecular interactions and use of glycans in biomedical applications currently rely on chemical and chemoenzymatic syntheses associated with considerable labor, waste, and costs. Here, we develop a sustainable and scalable method for production of glycans in glycoengineered mammalian cells by employing secreted Glycocarriers with repeat glycosylation acceptor sequence motifs for different glycans. The Glycocarrier technology provides a flexible production platform for glycans in different formats, including oligosaccharides, glycopeptides, and multimeric glycomodules, and offers wide opportunities for use in bioassays and biomedical applications.

In silico analysis of aptamer-RNA conjugate interactions with human transferrin receptor

The human transmembrane protein Transferrin Receptor-1 is regarded as a promising target for the systemic delivery of therapeutic agents, particularly of nucleic acid therapeutics, such as short double stranded RNAs. This ubiquitous receptor is involved in cellular iron uptake, keeping intracellular homeostasis. It is overexpressed in multiple cancer cell types and is internalized via clathrin-mediated endocytosis. In previous studies, a human transferrin receptor-1 RNA aptamer, identified as TR14 ST1-3, was shown to be capable of effectively internalizing into cells in culture and to deliver small, double stranded RNAs in vitro and in vivo, via systemic administration. To understand, at the molecular level, the aptamer binding to the receptor and the impact of conjugation with the therapeutic RNA, a multi-level in silico protocol was employed, including protein-aptamer docking, molecular dynamics simulations and free energy calculations. The competition for the binding pocket, between the aptamer and the natural ligand human Transferrin, was also evaluated. The results show that the aptamer binds to the same region as Transferrin, with residues from the helical domain showing a critical role. Moreover, the conjugation to the therapeutic RNA, was shown not to affect aptamer binding. Overall, this study provides an atomic-level understanding of aptamer association to human Transferrin Receptor-1 and of its conjugation with a short model-therapeutic RNA, providing also important clues for futures studies aiming to deliver other oligonucleotide-based therapeutics via Transferrin Receptor.

Nonclinical Pharmacokinetics Study of OLX702A-075-16, N-Acetylgalactosamine Conjugated Asymmetric Small Interfering RNA (GalNAc-asiRNA)

In this study, the nonclinical pharmacokinetics of OLX702A-075-16, an RNA interference therapeutic currently in development, were investigated. OLX702A-075-16 is a novel N-acetylgalactosamine conjugated asymmetric small-interfering RNA (GalNAc-asiRNA) used for the treatment of an undisclosed liver disease. Its unique 16/21-mer asymmetric structure reduces nonspecific off-target effects without compromising efficacy. We investigated the plasma concentration, tissue distribution, metabolism, and renal excretion of OLX702A-075-16 following a subcutaneous administration in mice and rats. For bioanalysis, high-performance liquid chromatography with fluorescence detection was used. The results showed rapid clearance from plasma (0.5 to 1.5 hours of half-life) and predominant distribution to the liver and/or kidney. Less than 1% of the liver concentration of OLX702A-075-16 was detected in the other tissues. Metabolite profiling using liquid chromatography coupled with high-resolution mass spectrometry revealed that the intact duplex OLX702A-075-16 was the major compound in plasma. The GalNAc moiety was predominantly metabolized from the sense strand in the liver, with the unconjugated sense strand of OLX702A-075-16 accounting for more than 95% of the total exposure in the rat liver. Meanwhile, the antisense strand was metabolized by the sequential loss of nucleotides from the 3'-terminus by exonuclease, with the rat liver samples yielding the most diverse truncated forms of metabolites. Urinary excretion over 96 hours was less than 1% of the administered dose in rats. High plasma protein binding of OLX702A-075-16 likely inhibited its clearance through renal filtration. SIGNIFICANCE STATEMENT: This study presents the first comprehensive characterization of the in vivo pharmacokinetics of GalNAc-asiRNA. The pharmacokinetic insights gained from this research will aid in understanding toxicology and efficacy, optimizing delivery platforms, and improving the predictive power of preclinical species data for human applications.

Iron homeostasis and ferroptosis in human diseases: mechanisms and therapeutic prospects

Iron, an essential mineral in the body, is involved in numerous physiological processes, making the maintenance of iron homeostasis crucial for overall health. Both iron overload and deficiency can cause various disorders and human diseases. Ferroptosis, a form of cell death dependent on iron, is characterized by the extensive peroxidation of lipids. Unlike other kinds of classical unprogrammed cell death, ferroptosis is primarily linked to disruptions in iron metabolism, lipid peroxidation, and antioxidant system imbalance. Ferroptosis is regulated through transcription, translation, and post-translational modifications, which affect cellular sensitivity to ferroptosis. Over the past decade or so, numerous diseases have been linked to ferroptosis as part of their etiology, including cancers, metabolic disorders, autoimmune diseases, central nervous system diseases, cardiovascular diseases, and musculoskeletal diseases. Ferroptosis-related proteins have become attractive targets for many major human diseases that are currently incurable, and some ferroptosis regulators have shown therapeutic effects in clinical trials although further validation of their clinical potential is needed. Therefore, in-depth analysis of ferroptosis and its potential molecular mechanisms in human diseases may offer additional strategies for clinical prevention and treatment. In this review, we discuss the physiological significance of iron homeostasis in the body, the potential contribution of ferroptosis to the etiology and development of human diseases, along with the evidence supporting targeting ferroptosis as a therapeutic approach. Importantly, we evaluate recent potential therapeutic targets and promising interventions, providing guidance for future targeted treatment therapies against human diseases.

Inhibitory Effects on RNA Binding and RNase H Induction Activity of Prodrug-Type Oligodeoxynucleotides Modified with a Galactosylated Self-Immolative Linker Cleavable by β-Galactosidase

Prodrug-type oligonucleotides (prodrug-ONs) are a class of oligonucleotide designed for activation under specific intracellular conditions or external stimuli. Prodrug-ONs can be activated in the target tissues or cells, thereby reducing the risk of adverse effects. In this study, we synthesized prodrug-type oligodeoxynucleotides activated by β-galactosidase, an enzyme that is overexpressed in cancer and senescent cells. These oligodeoxynucleotides (ODNs) contain a modified thymidine conjugated with galactose via a self-immolative linker at the O4-position. UV-melting analysis revealed that the modifications decreased the melting temperature (Tm) compared with that of the unmodified ODN when hybridized with complementary RNA. Furthermore, cleavage of the glycosidic bond by β-galactosidase resulted in the spontaneous removal of the linker from the nucleobase moiety, generating unmodified ODNs. Additionally, the introduction of multiple modified thymidines into ODNs completely inhibited the RNase H-mediated cleavage of complementary RNA. These findings suggest the possibility of developing prodrug-ONs, which are specifically activated in cancer cells or senescent cells with high β-galactosidase expression.

Non-Viral RNA Delivery During Pregnancy: Opportunities and Challenges

During pregnancy, the risk of maternal and fetal adversities increases due to physiological changes, genetic predispositions, environmental factors, and infections. Unfortunately, treatment options are severely limited because many essential interventions are unsafe, inaccessible, or lacking in sufficient scientific data to support their use. One potential solution to this challenge may lie in emerging RNA therapeutics for gene therapy, protein replacement, maternal vaccination, fetal gene editing, and other prenatal treatment applications. In this review, the current landscape of RNA platforms and non-viral RNA delivery technologies that are under active development for administration during pregnancy is explored. Advancements of pregnancy-specific RNA drugs against SARS-CoV-2, Zika, influenza, preeclampsia, and for in-utero gene editing are discussed. Finally, this study highlights bottlenecks that are impeding translation efforts of RNA therapies, including the lack of accurate cell-based and animal models of human pregnancy and concerns related to toxicity and immunogenicity during pregnancy. Overcoming these challenges will facilitate the rapid development of this new class of pregnancy-safe drugs.

The future of therapeutic options for hereditary angioedema

Hereditary angioedema (HAE) is a rare genetic condition causing unpredictable and severe episodes of angioedema that are debilitating and life-threatening. Moreover, HAE can be classified into HAE due to C1-esterase inhibitor deficiency (HAE-C1INH) or HAE with normal C1INH. Moreover, HAE-C1INH is subcategorized as types I and II based on deficient or dysfunctional circulating C1INH protein resulting from inherited or spontaneous mutations in the SERPING1 gene leading to uncontrolled factor XII/plasma kallikrein activation and excessive bradykinin production. Bradykinin-2 receptor activation leads to vasodilation, increased vascular permeability, and smooth muscle contractions, resulting in subcutaneous or submucosal fluid extravasation that can affect the face, extremities, airway, and gastrointestinal and genitourinary systems. Furthermore, HAE with normal C1INH is caused by either a known or unknown genetic mutation, and the mechanisms are less well-established but most forms are thought to be related to bradykinin signaling with a similar presentation as HAE-C1INH despite normal levels of C1INH protein and function. Current HAE management strategies include on-demand and prophylactic treatments which replace C1INH, reduce kallikrein activity, or block bradykinin binding to the bradykinin B2 receptor. With the advent of additional small molecule inhibitors, monoclonal antibodies, RNA-targeted therapies, gene therapies, and gene modification approaches, preclinical studies and human clinical trials are underway to further expand therapeutic options in HAE. This review article will briefly summarize current HAE treatments and provide an overview of potential future therapies for HAE.

Advances in nucleic acid-targeted therapies for cardiovascular disease prevention

Nucleic acid-based therapies are being rapidly developed for prevention and management of cardiovascular diseases (CVD). Remarkable advancements have been achieved in the delivery, safety, and effectiveness of these therapeutics in the past decade. These therapies can also modulate therapeutic targets that cannot be sufficiently addressed using traditional drugs or antibodies. Among the nucleic acid-targeted therapeutics under development for CVD prevention are RNA-targeted approaches, including antisense oligonucleotides (ASO), small interfering RNAs (siRNA), and novel genome editing techniques. Genetic studies have identified potential therapeutic targets that are suggested to play a causative role in development and progression of CVD. RNA- and DNA-targeted therapeutics can be particularly well delivered to the liver, where atherogenic lipoproteins and angiotensinogen (AGT) are produced. Current targets in lipid metabolism include proprotein convertase subtilisin/kexin type 9 (PCSK9), apolipoprotein A (ApoA), apolipoprotein C3 (ApoC3), angiopoietin-like 3 (ANGPTL3). Several large-scale clinical development programs for nucleic acid-targeted therapies in cardiovascular prevention are under way, which may also be attractive from a therapy adherence point of view, given the long action of these therapeutics. In addition to genome editing, the concept of gene transfer is presently under assessment in preclinical and clinical investigations as a potential approach for addressing low-density lipoprotein receptor deficiency. Furthermore, ongoing research is exploring the use of RNA-targeted therapies to treat arterial hypertension by reducing hepatic angiotensinogen (AGT) production. This review summarizes the rapid translation of siRNA and ASO therapeutics as well as gene editing into clinical studies to treat dyslipidemia and arterial hypertension for CVD prevention. It also outlines potential innovative therapeutic options that are likely relevant to the future of cardiovascular medicine.

Systematic Review of Genetic Substrate Reduction Therapy in Lysosomal Storage Diseases: Opportunities, Challenges and Delivery Systems

BACKGROUND

Genetic substrate reduction therapy (gSRT), which involves the use of nucleic acids to downregulate the genes involved in the biosynthesis of storage substances, has been investigated in the treatment of lysosomal storage diseases (LSDs).

OBJECTIVE

To analyze the application of gSRT to the treatment of LSDs, identifying the silencing tools and delivery systems used, and the main challenges for its development and clinical translation, highlighting the contribution of nanotechnology to overcome them.

METHODS

A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines was performed. PubMed, Scopus, and Web of Science databases were used for searching terms related to LSDs and gene-silencing strategies and tools.

RESULTS

Fabry, Gaucher, and Pompe diseases and mucopolysaccharidoses I and III are the only LSDs for which gSRT has been studied, siRNA and lipid nanoparticles being the silencing strategy and the delivery system most frequently employed, respectively. Only in one recently published study was CRISPR/Cas9 applied to treat Fabry disease. Specific tissue targeting, availability of relevant cell and animal LSD models, and the rare disease condition are the main challenges with gSRT for the treatment of these diseases. Out of the 11 studies identified, only two gSRT studies were evaluated in animal models.

CONCLUSIONS

Nucleic acid therapies are expanding the clinical tools and therapies currently available for LSDs. Recent advances in CRISPR/Cas9 technology and the growing impact of nanotechnology are expected to boost the clinical translation of gSRT in the near future, and not only for LSDs.

Advances in nucleic acid therapeutics: structures, delivery systems, and future perspectives in cancer treatment

Cancer has emerged as a significant threat to human health. Nucleic acid therapeutics regulate the gene expression process by introducing exogenous nucleic acid fragments, offering new possibilities for tumor remission and even cure. Their mechanism of action and high specificity demonstrate great potential in cancer treatment. However, nucleic acid drugs face challenges such as low stability and limited ability to cross physiological barriers in vivo. To address these issues, various nucleic acid delivery vectors have been developed to enhance the stability and facilitate precise targeted delivery of nucleic acid drugs within the body. In this review article, we primarily introduce the structures and principles of nucleic acid drugs commonly used in cancer therapy, as well as their cellular uptake and intracellular transportation processes. We focus on the various vectors commonly employed in nucleic acid drug delivery, highlighting their research progress and applications in recent years. Furthermore, we propose potential trends and prospects of nucleic acid drugs and their carriers in the future.

Established and Emerging Nucleic Acid Therapies for Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is a genetic disease that leads to elevated low-density lipoprotein cholesterol levels and risk of coronary heart disease. Current therapeutic options for FH remain relatively limited and only partially effective in both lowering low-density lipoprotein cholesterol and modifying coronary heart disease risk. The unique characteristics of nucleic acid therapies to target the underlying cause of the disease can offer solutions unachievable with conventional medications. DNA- and RNA-based therapeutics have the potential to transform the care of patients with FH. Recent advances are overcoming obstacles to clinical translation of nucleic acid-based medications, including greater stability of the formulations as well as site-specific delivery, making gene-based therapy for FH an alternative approach for treatment of FH.

RNA nanomedicine in liver diseases

The remarkable impact of RNA nanomedicine during the COVID-19 pandemic has demonstrated the expansive therapeutic potential of this field in diverse disease contexts. In recent years, RNA nanomedicine targeting the liver has been paradigm-shifting in the management of metabolic diseases such as hyperoxaluria and amyloidosis. RNA nanomedicine has significant potential in the management of liver diseases, where optimal management would benefit from targeted delivery, doses titrated to liver metabolism, and personalized therapy based on the specific site of interest. In this review, we discuss in-depth the different types of RNA and nanocarriers used for liver targeting along with their specific applications in metabolic dysfunction-associated steatotic liver disease, liver fibrosis, and liver cancers. We further highlight the strategies for cell-specific delivery and future perspectives in this field of research with the emergence of small activating RNA, circular RNA, and RNA base editing approaches.

Hepatic Surf4 Deficiency Impairs Serum Amyloid A1 Secretion and Attenuates Liver Fibrosis in Mice

Liver fibrosis is a severe global health problem. However, no effective antifibrotic drugs have been approved. Surf4 is primarily located in the endoplasmic reticulum (ER) and mediates the transport of secreted proteins from the ER to the Golgi apparatus. Knockout of hepatic Surf4 (Surf4 LKO) in mice impairs very-low-density lipoprotein secretion without causing overt liver damage. Here, we found that collagen levels are significantly reduced in the liver of Surf4 LKO mice compared with control Surf4 flox mice, as demonstrated by proteomics, Western blot, and quantitative reverse transcription polymerase chain reaction. Therefore, this study aims to investigate whether and how hepatic Surf4 affects liver fibrosis. We observed that CCl4-induced liver fibrosis is significantly lower in Surf4 LKO mice than in Surf4 flox mice. Mechanistically, hepatic Surf4 deficiency reduces serum amyloid A1 (SAA1) secretion and hepatic stellate cell (HSC) activation. Surf4 coimmunoprecipitates and colocalizes with SAA1. Lack of hepatic Surf4 significantly reduces SAA1 secretion from hepatocytes, and SAA1 activates cultured human HSCs (LX-2 cells). Conditioned medium (CM) from Surf4-deficient primary hepatocytes activates LX-2 cells to a much lesser extent than CM from Surf4 flox primary hepatocytes, and this reduced effect is restored by the addition of recombinant SAA1 to CM from Surf4-deficient hepatocytes. Knockdown of SAA1 in primary hepatocytes or TLR2 in LX-2 cells significantly reduces LX-2 activation induced by CM from Surf4 flox hepatocytes but not from Surf4 LKO hepatocytes. Furthermore, knockdown of SAA1 significantly ameliorates liver fibrosis in Surf4 flox mice but does not further reduce liver fibrosis in Surf4 LKO mice. We also observe substantial expression of Surf4 and SAA1 in human fibrotic livers. Therefore, hepatic Surf4 facilitates SAA1 secretion, activates HSCs, and aggravates liver fibrosis, suggesting that hepatic Surf4 and SAA1 may serve as treatment targets for liver fibrosis.

Systemic Brain Delivery of Oligonucleotide Therapeutics Enhanced by Protein Corona-Assisted DNA Cubes

The systemic delivery of oligonucleotide therapeutics to the brain is challenging but highly desirable for the treatment of brain diseases undruggable with traditional small-molecule drugs. In this study, a set of DNA nanostructures is prepared and screened them to develop a protein corona-assisted platform for the brain delivery of oligonucleotide therapeutics. The biodistribution analysis of intravenously injected DNA nanostructures reveals that a cube-shaped DNA nanostructure (D-Cb) can penetrate the brain-blood barrier (BBB) and reach the brain tissue. The brain distribution level of D-Cb is comparable to that of other previous nanoparticles conjugated with brain-targeting ligands. Proteomic analysis of the protein corona formed on D-Cb suggests that its brain distribution is driven by endothelial receptor-targeting ligands in the protein corona, which mediate transcytosis for crossing the BBB. D-Cb is subsequently used to deliver an antisense oligonucleotide (ASO) to treat glioblastoma multiforme (GBM) in mice. While free ASO is unable to reach the brain, ASO loaded onto D-Cb is delivered efficiently to the brain tumor region, where it downregulates the target gene and exerts an anti-tumor effect on GBM. D-Cb is expected to serve as a viable platform based on protein corona formation for systemic brain delivery of oligonucleotide therapeutics.

RNA therapeutics to control fibrinolysis: review on applications in biology and medicine

Regulation of fibrinolysis, the process that degrades blood clots, is pivotal in maintaining hemostasis. Dysregulation leads to thrombosis or excessive bleeding. Proteins in the fibrinolysis system include fibrinogen, coagulation factor XIII, plasminogen, tissue plasminogen activator, urokinase plasminogen activator, α2-antiplasmin, thrombin-activatable fibrinolysis inhibitor, plasminogen activator inhibitor-1, α2-macroglobulin, and others. While each of these is a potential therapeutic target for diseases, they lack effective or long-acting inhibitors. Rapid advances in RNA-based technologies are creating powerful tools to control the expression of proteins. RNA agents can be long-acting and tailored to either decrease or increase production of a specific protein. Advances in nucleic acid delivery, such as by lipid nanoparticles, have enabled the delivery of RNA to the liver, where most proteins of coagulation and fibrinolysis are produced. This review will summarize the classes of RNA that induce 1) inhibition of protein synthesis, including small interfering RNA and antisense oligonucleotides; 2) protein expression, including messenger RNA and self-amplifying RNA; and 3) gene editing for gene knockdown and precise editing. It will review specific examples of RNA therapies targeting proteins in the coagulation and fibrinolysis systems and comment on the wide range of opportunities for controlling fibrinolysis for biological applications and future therapeutics using state-of-the-art RNA therapies.

Precision targeting in oncology: The future of conjugated drugs

Coupled drugs, especially antibody-coupled drugs (ADCs), are a hot topic in oncology. As the development of ADCs has progressed, different coupling modes have emerged, inspired by their structural design have emerged. Technological advances have led to interweaving and collision of old and new concepts of coupled drugs, and have even challenged the concepts and techniques of coupled drugs at this stage. For example, antibody-oligonucleotide conjugates are a new class of chimeric biomolecules synthesized by coupling oligonucleotides with monoclonal antibodies through linkers, offering precise targeting and improved pharmacokinetic properties. This study aimed to elucidate the mechanism of action of coupled drugs and their current development status in antitumor therapy to provide better strategies for antitumor therapy.

A GalNAc-modified CaCO3 nano-immunomodulator for targeted and responsive immunotherapy against orthotopic liver cancer

A nano-immunomodulator modified with N-acetylgalactosamine (GalNAc) on calcium carbonate (CaCO3) was prepared for targeted and responsive immunotherapy. And the immunologic adjuvant (CpG ODNs) and doxorubicin (DOX) were released to synergistically improve immune response for treating orthotopic liver cancer.