Nucleic Acid Delivery to the Vascular Endothelium

Emerging Delivery Systems for Enabling Precision Nucleic Acid Therapeutics

Nucleic acid therapeutics represent a highly promising treatment approach in modern medicine, treating diseases at the genetic level. However, these therapeutics face numerous challenges in practical applications, particularly regarding their stability, effectiveness, cellular uptake efficiency, and limitations in delivering them specifically to target tissues. To overcome these obstacles, researchers have developed various innovative delivery systems, including viral vectors, lipid nanoparticles, polymer nanoparticles, inorganic nanoparticles, protein carriers, exosomes, antibody oligonucleotide conjugates, and DNA nanostructure-based delivery systems. These systems enhance the therapeutic efficacy of nucleic acid drugs by improving their stability, targeting specificity, and half-life in vivo. In this review, we systematically discuss different types of nucleic acid drugs, analyze the major barriers encountered in their delivery, and summarize the current research progress in emerging delivery systems. We also highlight the latest advancements in the application of these systems for treating genetic diseases, infectious diseases, cancer, brain diseases, and wound healing. This review aims to provide a comprehensive overview of nucleic acid drug delivery systems' current status and future directions by integrating the latest advancements in nanotechnology, biomaterials science, and gene editing technologies, emphasizing their transformative potential in precision medicine.

Non-coding RNAs to treat vascular smooth muscle cell dysfunction

Vascular smooth muscle cell (vSMC) dysfunction is a critical contributor to cardiovascular diseases, including atherosclerosis, restenosis and vein graft failure. Recent advances have unveiled a fascinating range of non-coding RNAs (ncRNAs) that play a pivotal role in regulating vSMC function. This review aims to provide an in-depth analysis of the mechanisms underlying vSMC dysfunction and the therapeutic potential of various ncRNAs in mitigating this dysfunction, either preventing or reversing it. We explore the intricate interplay of microRNAs, long-non-coding RNAs and circular RNAs, shedding light on their roles in regulating key signalling pathways associated with vSMC dysfunction. We also discuss the prospects and challenges associated with developing ncRNA-based therapies for this prevalent type of cardiovascular pathology. LINKED ARTICLES: This article is part of a themed issue Non-coding RNA Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.2/issuetoc.

Nanocarriers for targeted drug delivery in the vascular system: focus on endothelium

Endothelial cells (ECs) are pivotal in maintaining vascular health, regulating hemodynamics, and modulating inflammatory responses. Nanocarriers hold transformative potential for precise drug delivery within the vascular system, particularly targeting ECs for therapeutic purposes. However, the complex interactions between vascular ECs and nanocarriers present significant challenges for the development and clinical translation of nanotherapeutics. This review assesses recent advancements and key strategies in employing nanocarriers for drug delivery to vascular ECs. It suggested that through precise physicochemical design and surface modifications, nanocarriers can enhance targeting specificity and improve drug internalization efficiency in ECs. Additionally, we elaborated on the applications of nanocarriers specifically designed for targeting ECs in the treatment of cardiovascular diseases, cancer metastasis, and inflammatory disorders. Despite these advancements, safety concerns, the complexity of in vivo processes, and the challenge of achieving subcellular drug delivery remain significant obstacles to the effective targeting of ECs with nanocarriers. A comprehensive understanding of endothelial cell biology and its interaction with nanocarriers is crucial for realizing the full potential of targeted drug delivery systems.

Potentiation of anti-angiogenic eNOS-siRNA transfection by ultrasound-mediated microbubble destruction in ex vivo rat aortic rings

Nitric oxide (NO) regulates vascular homeostasis and plays a key role in revascularization and angiogenesis. The endothelial nitric oxide synthase (eNOS) enzyme catalyzes NO production in endothelial cells. Overexpression of the eNOS gene has been implicated in pathologies with dysfunctional angiogenic processes, such as cancer. Therefore, modulating eNOS gene expression using small interfering RNAs (siRNAs) represents a viable strategy for antitumor therapy. siRNAs are highly specific to the target gene, thus reducing off-target effects. Given the widespread distribution of endothelium and the crucial physiological role of eNOS, localized delivery of nucleic acid to the affected area is essential. Therefore, the development of an efficient eNOS-siRNA delivery carrier capable of controlled release is imperative for targeting specific vascular regions, particularly those associated with tumor vascular growth. Thus, this study aims to utilize ultrasound-mediated microbubble destruction (UMMD) technology with cationic microbubbles loaded with eNOS-siRNA to enhance transfection efficiency and improve siRNA delivery, thereby preventing sprouting angiogenesis. The efficiency of eNOS-siRNA transfection facilitated by UMMD was assessed using bEnd.3 cells. Synthesis of nitric oxide and eNOS protein expression were also evaluated. The silencing of eNOS gene in a model of angiogenesis was assayed using the rat aortic ring assay. The results showed that from 6 to 24 h, the transfection of fluorescent siRNA with UMMD was twice as high as that of lipofection. Moreover, transfection of eNOS-siRNA with UMMD enhanced the knockdown level (65.40 ± 4.50%) compared to lipofectamine (40 ± 1.70%). Silencing of eNOS gene with UMMD required less amount of eNOS-siRNA (42 ng) to decrease the level of eNOS protein expression (52.30 ± 0.08%) to the same extent as 79 ng of eNOS-siRNA using lipofectamine (56.30 ± 0.10%). NO production assisted by UMMD was reduced by 81% compared to 67% reduction transfecting with lipofectamine. This diminished NO production led to higher attenuation of aortic ring outgrowth. Three-fold reduction compared to lipofectamine transfection. In conclusion, we propose the combination of eNOS-siRNA and UMMD as an efficient, safe, non-viral nucleic acid transfection strategy for inhibition of tumor progression.

Influencing Endothelial Cells' Roles in Inflammation and Wound Healing Through Nucleic Acid Delivery

Tissue engineering and wound-healing interventions are often designed for use in diseased and inflamed environments. In this space, endothelial cells (ECs) are crucial regulators of inflammation and healing, as they are the primary contact for recruitment of immune cells, as well as production of proinflammatory cytokines, which can stimulate or reduce inflammation. Alternatively, proliferation and spreading of ECs result in the formation of new vascular tissue or repair of damaged tissue, both critical for wound healing. Targeting ECs with specific nucleic acids could reduce unwanted inflammation or promote tissue regeneration as needed, which are two large issues involved in many regenerative medicine goals. Polymeric delivery systems are tools that can control the delivery of nucleic acids and prolong their effects. This review describes the use of polymeric vehicles for the delivery of nucleic acids to ECs for tissue engineering. Impact statement Tissue engineering is a rapidly growing field that has the potential to resolve many disease states and improve the quality of life of patients. In some applications, tissue-engineered strategies or constructs are developed to rebuild spaces damaged by disease or degeneration. To rebuild the native tissue, these constructs may need to interact with unwanted immune activity and cells. Various immune cells are often the focus of therapies as they are critical players in the inflammatory response; however, endothelial cells are also an extremely important and promising target in these cases. In addition, controlled delivery of specific-acting molecules, such as nucleic acids, is of growing interest for the regeneration and health of a variety of different tissues. It is important to understand what has been done and the potential of these targets and therapeutics for future investigation and advancements in tissue engineering.

Polymeric Vehicles for Nucleic Acid Delivery: Enhancing the Therapeutic Efficacy and Cellular Uptake

BACKGROUND

Therapeutic gene delivery may be facilitated by the use of polymeric carriers. When combined with nucleic acids to form nanoparticles or polyplexes, a variety of polymers may shield the cargo from in vivo breakdown and clearance while also making it easier for it to enter intracellular compartments.

AIM AND OBJECTIVES

Polymer synthesis design choices result in a wide variety of compounds and vehicle compositions. Depending on the application, these characteristics may be changed to provide enhanced endosomal escape, longer-lasting distribution, or stronger connection with nucleic acid cargo and cells. Here, we outline current methods for delivering genes in preclinical and clinical settings using polymers.

METHODOLOGY

Significant therapeutic outcomes have previously been attained using genetic material- delivering polymer vehicles in both in-vitro and animal models. When combined with nucleic acids to form nanoparticles or polyplexes, a variety of polymers may shield the cargo from in vivo breakdown and clearance while also making it easier for it to enter intracellular compartments. Many innovative diagnoses for nucleic acids have been investigated and put through clinical assessment in the past 20 years.

RESULTS

Polymer-based carriers have additional delivery issues due to their changes in method and place of biological action, as well as variances in biophysical characteristics. We cover recent custom polymeric carrier architectures that were tuned for nucleic acid payloads such genomemodifying nucleic acids, siRNA, microRNA, and plasmid DNA.

CONCLUSION

In conclusion, the development of polymeric carriers for gene delivery holds promise for therapeutic applications. Through careful design and optimization, these carriers can overcome various challenges associated with nucleic acid delivery, offering new avenues for treating a wide range of diseases.

Repression of rRNA gene transcription by endothelial SPEN deficiency normalizes tumor vasculature via nucleolar stress

Human cancers induce a chaotic, dysfunctional vasculature that promotes tumor growth and blunts most current therapies; however, the mechanisms underlying the induction of a dysfunctional vasculature have been unclear. Here, we show that split end (SPEN), a transcription repressor, coordinates rRNA synthesis in endothelial cells (ECs) and is required for physiological and tumor angiogenesis. SPEN deficiency attenuated EC proliferation and blunted retinal angiogenesis, which was attributed to p53 activation. Furthermore, SPEN knockdown activated p53 by upregulating noncoding promoter RNA (pRNA), which represses rRNA transcription and triggers p53-mediated nucleolar stress. In human cancer biopsies, a low endothelial SPEN level correlated with extended overall survival. In mice, endothelial SPEN deficiency compromised rRNA expression and repressed tumor growth and metastasis by normalizing tumor vessels, and this was abrogated by p53 haploinsufficiency. rRNA gene transcription is driven by RNA polymerase I (RNPI). We found that CX-5461, an RNPI inhibitor, recapitulated the effect of Spen ablation on tumor vessel normalization and combining CX-5461 with cisplatin substantially improved the efficacy of treating tumors in mice. Together, these results demonstrate that SPEN is required for angiogenesis by repressing pRNA to enable rRNA gene transcription and ribosomal biogenesis and that RNPI represents a target for tumor vessel normalization therapy of cancer.