VCAM-1-binding peptide targeted cationic liposomes containing NLRP3 siRNA to modulate LDL transcytosis as a novel therapy for experimental atherosclerosis

Siglec-5 as a novel receptor mediates endothelial cells oxLDL transcytosis to promote atherosclerosis

BACKGROUND

Excessive subendothelial retention of oxidized low-density lipoprotein (oxLDL) and subsequent oxLDL engulfment by macrophages leads to the formation of foam cells and the development of atherosclerosis. Our previous study showed that the plasma level of sialic acid-binding immunoglobulin-like lectin 5 (Siglec-5) was a novel biomarker for the prognosis of atherosclerosis in diabetic patients. However, the role and underlying mechanisms of Siglec-5 in atherosclerosis have not been elucidated.

METHODS

The interaction between oxLDL and Siglec-5 was detected by fluorescence colocalization and coimmunoprecipitation. The effect of oxLDL on Siglec-5 expression was detected in endothelial cells and macrophages, and the effect of Siglec-5 on oxLDL transcytosis and uptake was investigated. Siglec-5 was overexpressed in mice using recombinant adeno-associated virus vector serotype 9 (rAAV9-Siglec-5) to evaluate the effect of Siglec-5 on oxLDL uptake and atherogenesis in vivo. In addition, the effects of Siglec-5 antibodies and soluble Siglec-5 proteins on oxLDL transcytosis and uptake and their role in atherogenesis were investigated in vivo and in vitro.

RESULTS

We found that oxLDL interacted with Siglec-5 and that oxLDL stimulated the expression of Siglec-5. Siglec-5 promotes the transcytosis and uptake of oxLDL, while both anti-Siglec-5 antibodies and soluble Siglec-5 protein attenuated oxLDL transcytosis and uptake. Interestingly, overexpression of Siglec-5 by recombinant adeno-associated viral vector serotype 9 (rAAV9-Siglec-5) promoted the retention of oxLDL in the aorta of C57BL/6 mice. Moreover, overexpression of Siglec-5 significantly accelerated the formation of atherosclerotic lesions in Apoe-/- mice. Moreover, both anti-Siglec-5 antibodies and soluble Siglec-5 protein significantly alleviated the retention of oxLDL in the aorta of rAAV9-Siglec-5-transfected C57BL/6 mice and the formation of atherosclerotic plaques in rAAV9-Siglec-5-transfected Apoe-/- mice.

CONCLUSION

Our results suggested that Siglec-5 was a novel receptor that mediated oxLDL transcytosis and promoted the formation of foam cells. Interventions that inhibit the interaction between oxLDL and Siglec-5, including anti-Siglec-5 antibody or soluble Siglec-5 protein treatment, may provide novel therapeutic strategies in treating atherosclerosis.

Reactive Oxygen Species-Responsive Nanoparticle Delivery of Small Interfering Ribonucleic Acid Targeting Olfactory Receptor 2 for Atherosclerosis Theranostics

Atherosclerosis (AS) is a chronic inflammatory disorder characterized by arterial intimal lipid plaques. Small interfering ribonucleic acid (siRNA)-based therapies, with their ability to suppress specific genes with high targeting precision and minimal side effects, have shown great potential for AS treatment. However, targets of siRNA therapies based on macrophages for AS treatment are still limited. Olfactory receptor 2 (Olfr2), a potential target for plaque formation, was discovered recently. Herein, anti-Olfr2 siRNA (si-Olfr2) targeting macrophages was designed, and the theranostic platform encapsulating si-Olfr2 to target macrophages within atherosclerotic lesions was also developed, with the aim of downregulating Olfr2, as well as diagnosing AS through photoacoustic imaging (PAI) in the second near-infrared (NIR-II) window with high resolution. By utilization of a reactive oxygen species (ROS)-responsive nanocarrier system, the expression of Olfr2 on macrophages within atherosclerotic plaques was effectively downregulated, leading to the inhibition of NLR family pyrin domain containing 3 (NLRP3) inflammasome activation and interleukin-1 β (IL-1β) secretion, thereby reducing the formation of atherosclerotic plaques. As manifested by decreased Olfr2 expression, the lesions exhibited a significantly alleviated inflammatory response that led to reduced lipid deposition, macrophage apoptosis, and a noticeable decrease in the necrotic areas. This study provides a proof of concept for evaluating the theranostic nanoplatform to specifically deliver si-Olfr2 to lesional macrophages for AS diagnosis and treatment.

Shear-Sensitive circRNA-LONP2 Promotes Endothelial Inflammation and Atherosclerosis by Targeting NRF2/HO1 Signaling

Hemodynamic shear stress is a frictional force that acts on vascular endothelial cells and is essential for endothelial homeostasis. Physiological laminar shear stress (LSS) suppresses endothelial inflammation and protects arteries from atherosclerosis. Herein, we screened differentially expressed circular RNAs (circRNAs) that were significantly altered in LSS-stimulated endothelial cells and found that circRNA-LONP2 was involved in modulating the flow-dependent inflammatory response. Furthermore, endothelial circRNA-LONP2 overexpression promoted endothelial inflammation and atherosclerosis in vitro and in vivo. Mechanistically, circRNA-LONP2 competitively sponged miR-200a-3p and subsequently promoted Kelch-like ECH-associated protein 1, Yes-associated protein 1, and enhancer of zeste homolog 2 expression, thereby inactivating nuclear factor erythroid 2-related factor 2/heme oxygenase-1 signaling, promoting oxidative stress and endothelial inflammation, and accelerating atherosclerosis. LSS-induced down-regulation of circRNA-LONP2 suppresses endothelial inflammation, at least in part, by activating the miR-200a-3p-mediated nuclear factor erythroid 2-related factor 2/heme oxygenase-1 signaling pathway. CircRNA-LONP2 may serve as a new therapeutic target for atherosclerosis.

VCAM-1-targeted nanoparticles to diagnose, monitor and treat atherosclerosis

Vascular cell adhesion molecule-1 (VCAM-1) was identified over 2 decades ago as an endothelial adhesion receptor involved in leukocyte recruitment and cell-based immune responses. In atherosclerosis, a chronic inflammatory disease of the blood vessels that is the leading cause of death in the USA, endothelial VCAM-1 is robustly expressed beginning in the early stages of the disease. The interactions of circulating immune cells with VCAM-1 on the activated endothelial cell surface promote the uptake of monocytes and the progression of atherosclerotic lesions in susceptible vessels. Herein, we review the role of VCAM-1 in atherosclerosis and the use of VCAM-1 binding peptides, antibodies and aptamers as targeting agents for nanoplatforms for early detection and treatment of atherosclerotic disease.

Top Five Stories of the Cellular Landscape and Therapies of Atherosclerosis: Current Knowledge and Future Perspectives

Atherosclerosis (AS) is characterized by impairment and apoptosis of endothelial cells, continuous systemic and focal inflammation and dysfunction of vascular smooth muscle cells, which is documented as the traditional cellular paradigm. However, the mechanisms appear much more complicated than we thought since a bulk of studies on efferocytosis, transdifferentiation and novel cell death forms such as ferroptosis, pyroptosis, and extracellular trap were reported. Discovery of novel pathological cellular landscapes provides a large number of therapeutic targets. On the other side, the unsatisfactory therapeutic effects of current treatment with lipid-lowering drugs as the cornerstone also restricts the efforts to reduce global AS burden. Stem cell- or nanoparticle-based strategies spurred a lot of attention due to the attractive therapeutic effects and minimized adverse effects. Given the complexity of pathological changes of AS, attempts to develop an almighty medicine based on single mechanisms could be theoretically challenging. In this review, the top stories in the cellular landscapes during the initiation and progression of AS and the therapies were summarized in an integrated perspective to facilitate efforts to develop a multi-targets strategy and fill the gap between mechanism research and clinical translation. The future challenges and improvements were also discussed.

Nanotechnology-based non-viral vectors for gene delivery in cardiovascular diseases

Gene therapy is a technique that rectifies defective or abnormal genes by introducing exogenous genes into target cells to cure the disease. Although gene therapy has gained some accomplishment for the diagnosis and therapy of inherited or acquired cardiovascular diseases, how to efficiently and specifically deliver targeted genes to the lesion sites without being cleared by the blood system remains challenging. Based on nanotechnology development, the non-viral vectors provide a promising strategy for overcoming the difficulties in gene therapy. At present, according to the physicochemical properties, nanotechnology-based non-viral vectors include polymers, liposomes, lipid nanoparticles, and inorganic nanoparticles. Non-viral vectors have an advantage in safety, efficiency, and easy production, possessing potential clinical application value when compared with viral vectors. Therefore, we summarized recent research progress of gene therapy for cardiovascular diseases based on commonly used non-viral vectors, hopefully providing guidance and orientation for future relevant research.

Anti-atherosclerotic effects and molecular targets of ginkgolide B from Ginkgo biloba

Bioactive compounds derived from herbal medicinal plants modulate various therapeutic targets and signaling pathways associated with cardiovascular diseases (CVDs), the world's primary cause of death. Ginkgo biloba , a well-known traditional Chinese medicine with notable cardiovascular actions, has been used as a cardio- and cerebrovascular therapeutic drug and nutraceutical in Asian countries for centuries. Preclinical studies have shown that ginkgolide B, a bioactive component in Ginkgo biloba , can ameliorate atherosclerosis in cultured vascular cells and disease models. Of clinical relevance, several clinical trials are ongoing or being completed to examine the efficacy and safety of ginkgolide B-related drug preparations in the prevention of cerebrovascular diseases, such as ischemia stroke. Here, we present a comprehensive review of the pharmacological activities, pharmacokinetic characteristics, and mechanisms of action of ginkgolide B in atherosclerosis prevention and therapy. We highlight new molecular targets of ginkgolide B, including nicotinamide adenine dinucleotide phosphate oxidases (NADPH oxidase), lectin-like oxidized LDL receptor-1 (LOX-1), sirtuin 1 (SIRT1), platelet-activating factor (PAF), proprotein convertase subtilisin/kexin type 9 (PCSK9) and others. Finally, we provide an overview and discussion of the therapeutic potential of ginkgolide B and highlight the future perspective of developing ginkgolide B as an effective therapeutic agent for treating atherosclerosis.

Nanomedicine for Diagnosis and Treatment of Atherosclerosis

With the changing disease spectrum, atherosclerosis has become increasingly prevalent worldwide and the associated diseases have emerged as the leading cause of death. Due to their fascinating physical, chemical, and biological characteristics, nanomaterials are regarded as a promising tool to tackle enormous challenges in medicine. The emerging discipline of nanomedicine has filled a huge application gap in the atherosclerotic field, ushering a new generation of diagnosis and treatment strategies. Herein, based on the essential pathogenic contributors of atherogenesis, as well as the distinct composition/structural characteristics, synthesis strategies, and surface design of nanoplatforms, the three major application branches (nanodiagnosis, nanotherapy, and nanotheranostic) of nanomedicine in atherosclerosis are elaborated. Then, state-of-art studies containing a sequence of representative and significant achievements are summarized in detail with an emphasis on the intrinsic interaction/relationship between nanomedicines and atherosclerosis. Particularly, attention is paid to the biosafety of nanomedicines, which aims to pave the way for future clinical translation of this burgeoning field. Finally, this comprehensive review is concluded by proposing unresolved key scientific issues and sharing the vision and expectation for the future, fully elucidating the closed loop from atherogenesis to the application paradigm of nanomedicines for advancing the early achievement of clinical applications.

Colchicine delivered by a novel nanoparticle platform alleviates atherosclerosis by targeted inhibition of NF-κB/NLRP3 pathways in inflammatory endothelial cells

Atherosclerosis, a chronic inflammatory disease characterized by arterial plaque formation, is one of the most prominent causes of cardiovascular diseases. However, the current treatments often do not adequately compromise the chronic inflammation-mediated plaque accumulation and the disease progression. Therefore, a new and effective strategy that blocks atherosclerosis-associated inflammation is urgently needed to further reduce the risk. Colchicine, a potent anti-inflammatory medication, has shown great potential in the treatment of atherosclerosis, but its adverse effects have hampered its clinical application. Herein, we developed a novel delivery nanosystem encapsulated with colchicine (VHPK-PLGA@COL), which exhibited improved biosafety and sustained drug release along with the gradual degradation of PLGA and PEG as confirmed both in vitro and in vivo. Surface modification of the nanoparticles with the VHPK peptide ensured its capability to specifically target inflammatory endothelial cells and alleviate atherosclerotic plaque accumulation. In the ApoE - / - atherosclerotic mouse model, both colchicine and VHPK-PLGA@COL treatment significantly decreased the plaque area and enhanced plaque stability by blocking the NF-κB/NLRP3 pathways, while VHPK-PLGA@COL exhibited enhanced therapeutic effects due to its unique ability to target inflammatory endothelial cells without obvious long-term safety concerns. In summary, VHPK-PLGA@COL has the potential to overcome the key translational barriers of colchicine and open new avenues to repurpose this drug for anti-atherosclerotic therapy.

LDL Transcytosis by the Arterial Endothelium-Atherosclerosis by a Thousand Cuts?

PURPOSE OF REVIEW

The accumulation of LDL in the arterial intima is an initiating event in atherosclerosis. After decades of controversy, it is now clear that transcytosis of LDL across an intact endothelial monolayer contributes to its intimal deposition. We review recent observations in this field and address the question of whether LDL transcytosis can be manipulated therapeutically.

RECENT FINDINGS

The development of a live-cell imaging method for studying transcytosis using total internal reflection fluorescence (TIRF) microscopy has catalyzed recent discoveries. LDL transcytosis is mediated by SR-BI and ALK1. Estrogen down-regulates SR-BI and inhibits LDL transcytosis, while the nuclear structural protein HMGB1 promotes LDL transcytosis. LDL transcytosis by ALK1 is independent of the receptor's kinase activity and is antagonized by BMP9, ALK1's canonical ligand. Inflammation stimulates LDL transcytosis. Identifying the function and mechanisms of LDL transcytosis may ultimately permit its therapeutic manipulation.

Serum amyloid A and interleukin -1β facilitate LDL transcytosis across endothelial cells and atherosclerosis via NF-κB/caveolin-1/cavin-1 pathway

BACKGROUND AND AIMS

Inflammatory molecules play important roles in atherosclerosis. We aimed to illustrate the roles of serum amyloid A (SAA), and interleukin (IL)-1β in low density lipoproteins (LDL) transcytosis and atherosclerosis.

METHODS

Effects of SAA and IL-1β on transcytosis of LDL were measured by an in vitro LDL transcytosis model. NF-κB/caveolin-1/cavin-1 pathway activation was investigated by Western blots and ELISA. Effects of SAA and IL-1β on the retention of LDL in aorta of C57BL/6J mice were detected by IVIS spectrum. Effects of SAA and IL-1β on atherosclerosis in Apoe-/- mice were examined by Oil Red O staining.

RESULTS

SAA and IL-1β stimulated LDL transcytosis across endothelial cells (ECs), which was accompanied by an increase in LDL uptake by ECs. SAA and IL-1β enhanced the activity of nuclear factor (NF)-κB, consequently facilitating an up-regulation of proteins involved in caveolae formation, including caveolin-1 and cavin-1, along with an assembly of NLRP3 inflammasome. Furthermore, SAA- and IL-1β-induced effects were blocked by NF-κB subunit p65 siRNA. Meanwhile, SAA- and IL-1β-induced LDL transcytosis were effectively blocked by caveolin-1 siRNA or cavin-1 siRNA. Interestingly, SAA and IL-1β facilitated LDL entering into the aorta of C57BL/6J mice. In Apoe-/- mice, SAA and IL-1β increased the areas of lipid-rich atherosclerotic lesions in the both ascending and root of aorta. Furthermore, a significant increase in the NLRP3 inflammasome, accompanied by accumulation of cavin-1 and caveolin-1, was observed in the aortic endothelium of Apoe-/- mice.

CONCLUSIONS

SAA and IL-1β accelerated LDL transcytosis via the NF-κB/caveolin-1/cavin-1 axis.