Inhalation of an RNA aptamer that selectively binds extracellular histones protects from acute lung injury

RNA aptamer-mediated RNA nanotechnology for potential treatment of cardiopulmonary diseases

Ribonucleic acid (RNA) aptamers are single-stranded RNAs that bind to target proteins or other molecules with high specificity and affinity, modulating biological functions through distinct mechanisms. These aptamers can act n as antagonists to block pathological interactions, agonists to activate signaling pathways, or delivery vehicles for therapeutic cargos such as siRNAs and miRNAs. The advances in RNA nanotechnology further enhances the versatility of RNA aptamers, offering scalable platforms for engineering. In this review, we have summarized recent developments in RNA aptamer-mediated RNA nanotechnology and provide an overview of its potential in treating cardiovascular and respiratory disorders, including atherosclerosis, acute coronary syndromes, heart failure, lung cancer, pulmonary hypertension, asthma, chronic obstructive pulmonary disease (COPD), acute lung injury, viral respiratory infections, and pulmonary fibrosis. By integrating aptamer technologies with innovative delivery systems, RNA aptamers hold the potential to revolutionize the treatment landscape for cardiopulmonary diseases.

Circulating Nucleosomes and Histones in the Development of Lung Injury and Sepsis

Cellular nucleosomes-the structural and functional units of chromatin-are inherently present in cells. During cellular damage or cell death, nucleosomes are released into circulation, either actively or passively. Once released, nucleosomes can become immunogenic entities through various mechanisms. The nucleosomal proteins in nucleosomes, called histones, play a pivotal role in inducing immunogenicity. However, intact nucleosomes are more immunogenic than the histones alone, as nucleosomal double-stranded deoxyribonucleic acid (dsDNA) enhances its immunogenic potential. Our recent study has shown that circulating histones are predominantly nucleosomal histones rather than free histones. Consequently, circulating histones primarily function as integral parts of circulating nucleosomes rather than acting independently. Circulating nucleosomes and their associated histones are implicated in the pathogenesis of a wide array of diseases. Notably, they are critical in the pathogenesis of lung injury and sepsis. These diseases have high morbidity and mortality rates and lack early diagnostic biomarkers. Further investigation is required to fully elucidate the role of circulating nucleosomes and their associated histones in disease processes. This review aims to discuss the current understanding of circulating nucleosomes and histones in the pathogenesis of lung injury and sepsis, with a focus on the underlying mechanisms.

Hemocompatible nucleosome-inspired heparin-mimicking hydrogel microspheres for safe and efficient extracorporeal removal of circulating histones in critically ill patients

Circulating histones have been identified as essential mediators that lead to hyperinflammation, platelet aggregation, coagulation cascade activation, endothelial cell injury, multiple organ dysfunction, and death in severe patients with sepsis, multiple trauma, COVID-19, acute liver failure, and pancreatitis. Clinical evidence suggests that plasma levels of circulating histones are positively associated with disease severity and survival in patients with such critical diseases. However, safe and efficient therapeutic strategies targeting circulating histones are lacking in current clinical practice. Extracorporeal blood purification, a widely used life support technique in intensive care units, is a promising therapeutic option for eliminating circulating histones. Inspired by electrostatic interactions between DNA chains and histones in natural nucleosomes, we propose a "one stone kills two birds" strategy to combat histone-related critical diseases by developing heparin-mimicking hydrogel microspheres (RCHMs). On one hand, the heparin-mimicking hydrogel structure inside RCHMs contains a large number of carboxyl and sulphonic acid groups by in situ cross-linking polymerization, which endows the RCHMs with excellent hemocompatibility. On the other hand, the RCHMs can adsorb circulating histones through electrostatic interactions. Our results demonstrate that the RCHMs do not cause significant hemolysis, blood cell activation and complement activation, with improved anti-protein contamination properties. The tailored RCHM microspheres (A3M1) can efficiently and selectively adsorb 91.16% of calf thymus histones with an adsorption capacity of 20.47 μg mg-1 within 4 h. Moreover, the RCHMs significantly attenuate histone-mediated thrombocytopenia, platelet aggregation, and endothelial cell death. Therefore, the RCHMs are promising hemoperfusion adsorbents for extracorporeal removal of circulating histones from the blood of critically ill patients, providing a new insight into the management of multiple histone-related disorders.

Emerging therapeutic strategies targeting extracellular histones for critical and inflammatory diseases: an updated narrative review

Extracellular histones are crucial damage-associated molecular patterns involved in the development and progression of multiple critical and inflammatory diseases, such as sepsis, pancreatitis, trauma, acute liver failure, acute respiratory distress syndrome, vasculitis and arthritis. During the past decade, the physiopathologic mechanisms of histone-mediated hyperinflammation, endothelial dysfunction, coagulation activation, neuroimmune injury and organ dysfunction in diseases have been systematically elucidated. Emerging preclinical evidence further shows that anti-histone strategies with either their neutralizers (heparin, heparinoids, nature plasma proteins, small anion molecules and nanomedicines, etc.) or extracorporeal blood purification techniques can significantly alleviate histone-induced deleterious effects, and thus improve the outcomes of histone-related critical and inflammatory animal models. However, a systemic evaluation of the efficacy and safety of these histone-targeting therapeutic strategies is currently lacking. In this review, we first update our latest understanding of the underlying molecular mechanisms of histone-induced hyperinflammation, endothelial dysfunction, coagulopathy, and organ dysfunction. Then, we summarize the latest advances in histone-targeting therapy strategies with heparin, anti-histone antibodies, histone-binding proteins or molecules, and histone-affinity hemoadsorption in pre-clinical studies. Finally, challenges and future perspectives for improving the clinical translation of histone-targeting therapeutic strategies are also discussed to promote better management of patients with histone-related diseases.

Aptamers in neuro-oncology: An emerging therapeutic modality

Despite recent advances in the understanding of brain tumor pathophysiology, challenges associated with tumor location and characteristics have prevented significant improvement in neuro-oncology therapies. Aptamers are short, single-stranded DNA or RNA oligonucleotides that fold into sequence-specific, 3-dimensional shapes that, like protein antibodies, interact with targeted ligands with high affinity and specificity. Aptamer technology has recently been applied to neuro-oncology as a potential approach to innovative therapy. Preclinical research has demonstrated the ability of aptamers to overcome some obstacles that have traditionally rendered neuro-oncology therapies ineffective. Potential aptamer advantages include their small size, ability in some cases to penetrate the blood-brain barrier, inherent lack of immunogenicity, and applicability for discovering novel biomarkers. Herein, we review recent reports of aptamer applications in neuro-oncology including aptamers found by cell- and in vivo- Systematic Evolution of Ligands by Exponential Enrichment approaches, aptamer-targeted therapeutic delivery modalities, and aptamers in diagnostics and imaging. We further identify crucial future directions for the field that will be important to advance aptamer-based drugs or tools to clinical application in neuro-oncology.

Unlocking the potential of RNA-based therapeutics in the lung: current status and future directions

Awareness of RNA-based therapies has increased after the widespread adoption of mRNA vaccines against SARS-CoV-2 during the COVID-19 pandemic. These mRNA vaccines had a significant impact on reducing lung disease and mortality. They highlighted the potential for rapid development of RNA-based therapies and advances in nanoparticle delivery systems. Along with the rapid advancement in RNA biology, including the description of noncoding RNAs as major products of the genome, this success presents an opportunity to highlight the potential of RNA as a therapeutic modality. Here, we review the expanding compendium of RNA-based therapies, their mechanisms of action and examples of application in the lung. The airways provide a convenient conduit for drug delivery to the lungs with decreased systemic exposure. This review will also describe other delivery methods, including local delivery to the pleura and delivery vehicles that can target the lung after systemic administration, each providing access options that are advantageous for a specific application. We present clinical trials of RNA-based therapy in lung disease and potential areas for future directions. This review aims to provide an overview that will bring together researchers and clinicians to advance this burgeoning field.