Synthetic High-Density Lipoprotein-Mediated Targeted Delivery of Liver X Receptors Agonist Promotes Atherosclerosis Regression

Synthesis and bioactivity of a novel surfactin-based lipopeptide for mRNA delivery

The effective delivery of messenger ribonucleic acid (mRNA) to specific cell types and target tissues poses a significant challenge in nonviral therapeutic strategies. Lipid-based nanoparticles (LNPs) have emerged as a leading carrier system for delivering mRNA, particularly for infectious diseases, such as COVID-19. This study aimed to describe the synthesis of a novel lipopeptide based on surfactin, a naturally occurring surfactant. Additionally, a series of novel LNPs were rationally designed, based on the modified surfactin, OleSurf, and were formulated and optimized. The physicochemical properties, morphologies, and stabilities of the particles were evaluated. All formulations containing OleSurf produced particles with a diameter <80 nm and an encapsulation efficiency >95%. OleSurf LNPs demonstrated excellent transfection efficiency and luciferase expression with no cytotoxicity, compared to lipofectamine 2000, a known transfection reagent, and were comparable to the DLin-MC3-DMA lipid. OleSurf-based LNPs behaved as efficient mRNA carriers and showed enhanced mRNA-binding capabilities, associated with facilitated intracellular release, endosomal escape, and protection from endonuclease degradation. In addition, OleSurf-LNPs showed a higher mRNA delivery efficiency, a more advantageous biodistribution pattern, and an improved safety profile in vivo. Overall, the novel OleSurf LNPs presented an optimal delivery platform for mRNA therapeutics.

Drug repurposing: A multi targetted approach to treat cardiac disease from existing classical drugs to modern drug discovery

Cardiovascular diseases (CVDs) are characterized by abnormalities in the heart, blood vessels, and blood flow. CVDs comprise a diverse set of health issues. There are several types of CVDs like stroke, endothelial dysfunction, thrombosis, atherosclerosis, plaque instability and heart failure. Identification of a new drug for heart disease takes longer duration and its safety efficacy test takes even longer duration of research and approval. This chapter explores drug repurposing, nano-therapy, and plant-based treatments for managing CVDs from existing drugs which saves time and safety issues with testing new drugs. Existing drugs like statins, ACE inhibitor, warfarin, beta blockers, aspirin and metformin have been found to be useful in treating cardiac disease. For better drug delivery, nano therapy is opening new avenues for cardiac research by targeting interleukin (IL), TNF and other proteins by proteome interactome analysis. Nanoparticles enable precise delivery to atherosclerotic plaques, inflammation areas, and damaged cardiac tissues. Advancements in nano therapeutic agents, such as drug-eluting stents and drug-loaded nanoparticles are transforming CVDs management. Plant-based treatments, containing phytochemicals from Botanical sources, have potential cardiovascular benefits. These phytochemicals can mitigate risk factors associated with CVDs. The integration of these strategies opens new avenues for personalized, effective, and minimally invasive cardiovascular care. Altogether, traditional drugs, phytochemicals along with nanoparticles can revolutionize the future cardiac health care by identifying their signaling pathway, mechanism and interactome analysis.

Recent advancements in nanotechnology based drug delivery for the management of cardiovascular disease

Cardiovascular diseases (CVDs) constitute a predominant cause of both global mortality and morbidity. To address the challenges in the early diagnosis and management of CVDs, there is growing interest in the field of nanotechnology and nanomaterials to develop innovative diagnostic and therapeutic approaches. This review focuses on the recent advancements in nanotechnology-based diagnostic techniques, including cardiac immunoassays (CIA), cardiac circulating biomarkers, cardiac exosomal biomarkers, and molecular Imaging (MOI). Moreover, the article delves into the exciting developments in nanoparticles (NPs), biomimetic NPs, nanofibers, nanogels, and nanopatchs for cardiovascular applications. And discuss how these nanoscale technologies can improve the precision, sensitivity, and speed of CVD diagnosis and management. While highlighting their vast potential, we also address the limitations and challenges that must be overcome to harness these innovations successfully. Furthermore, this review focuses on the emerging opportunities for personalized and effective cardiovascular care through the integration of nanotechnology, ultimately aiming to reduce the global burden of CVDs.

Targeting Nanoplatform for Atherosclerosis Inhibition and Degradation via a Dual-Track Reverse Cholesterol Transport Strategy

As a main cause of serious cardiovascular diseases, atherosclerosis is characterized by deposited lipid and cholesterol crystals (CCs), which is considered as a great challenge to the current treatments. In this study, a dual-track reverse cholesterol transport strategy is used to overcome the cumulative CCs in the atherosclerotic lesions via a targeting nanoplatform named as LPLCH. Endowed with the active targeting ability to the plaques, the nanoparticles can be efficiently internalized and achieve a pH-triggered charge conversion for the escape from lysosomes. During this procedure, the liver X receptor (LXR) agonists loaded in nanoparticles are replaced by the deposited lysosomal CCs, leading to a LXR mediated up-regulation of ATP-binding cassette transporte ABCA1/G1 with the local CCs carrying at the same time. Thus, the cumulative CCs are removed in a dual-track way of ABCA1/G1 mediated efflux and nanoparticle-based carrying. The in vivo investigations indicate that LPLCH exhibits a favorable inhibition on the plaque progression and a further reversal of formed lesions when under a healthy diet. And the RNA-sequencing suggests that the cholesterol transport also synergistically activates the anti-inflammation effect. The dual-track reverse cholesterol transport strategy performed by LPLCH delivers an exciting candidate for the effective inhibition and degradation of atherosclerosis.

Combination of mangiferin and T0901317 targeting autophagy promotes cholesterol efflux from macrophage foam cell in atherosclerosis

BACKGROUND

The synthetic liver X receptor ligand (LXR) T0901317 (T0) has been reported to attenuate atherosclerosis (AS) without hyperglyceridemia due to innovative drug combination or nano-sized drug delivery. Given the key roles of mangiferin (MGF) in lipid metabolism and atherogenesis, it is critical to investigate progression of atherosclerotic lesion after combined treatment of MGF and T0.

METHODS

Atherosclerotic plaque formation and hepatic lipid accumulation were compared in Apoe-/- mice among T0 and/or MGF treatment. The in vitro functions of MGF and T0 were analyzed by Oil-red O staining, cholesterol efflux assay, transmission electron microscopy and western blot analyses with or without acetylated low density lipoprotein.

RESULTS

The combination therapy are effective regulators for atherosclerotic plaque formation in Apoe-/- mice, due to upregulation of ABCA1 and ABCG1 induced by LXR activation. Subsequently, we identified autophagy promoted by MGF and T0 treatment establishes a positive feedback loop that increases cholesterol efflux, resulted from LXRα activation. Under atherogenic conditions, the autophagy inhibitor CQ abolished the enhancement effect on cholesterol outflow of MGF and T0. Mechanically, MGF and T0 promotes LXRα and mTOR/AMPK signaling cascade in macrophage, and promotes AMPK signaling cascade in hepatocyte, leading to lipid metabolic homeostasis.

CONCLUSIONS

Altogether, our findings reveal that MGF and T0 engages in AS therapy without side effects by activating AMPK-dependent autophagy to promote macrophage cholesterol efflux, and MGF might serve as a natural compound to assist T0 in AS via targeting autophagy.

Multifunctional nanoparticle-mediated combining therapy for human diseases

Combining existing drug therapy is essential in developing new therapeutic agents in disease prevention and treatment. In preclinical investigations, combined effect of certain known drugs has been well established in treating extensive human diseases. Attributed to synergistic effects by targeting various disease pathways and advantages, such as reduced administration dose, decreased toxicity, and alleviated drug resistance, combinatorial treatment is now being pursued by delivering therapeutic agents to combat major clinical illnesses, such as cancer, atherosclerosis, pulmonary hypertension, myocarditis, rheumatoid arthritis, inflammatory bowel disease, metabolic disorders and neurodegenerative diseases. Combinatorial therapy involves combining or co-delivering two or more drugs for treating a specific disease. Nanoparticle (NP)-mediated drug delivery systems, i.e., liposomal NPs, polymeric NPs and nanocrystals, are of great interest in combinatorial therapy for a wide range of disorders due to targeted drug delivery, extended drug release, and higher drug stability to avoid rapid clearance at infected areas. This review summarizes various targets of diseases, preclinical or clinically approved drug combinations and the development of multifunctional NPs for combining therapy and emphasizes combinatorial therapeutic strategies based on drug delivery for treating severe clinical diseases. Ultimately, we discuss the challenging of developing NP-codelivery and translation and provide potential approaches to address the limitations. This review offers a comprehensive overview for recent cutting-edge and challenging in developing NP-mediated combination therapy for human diseases.

Phospholipids impact the protective effects of HDL-mimetic nanodiscs against lipopolysaccharide-induced inflammation

Aim: The impacts of synthetic high-density lipoprotein (sHDL) phospholipid components on anti-sepsis effects were investigated. Methods: sHDL composed with ApoA-I mimetic peptide (22A) and different phosphatidylcholines were prepared and characterized. Anti-inflammatory effects were investigated in vitro and in vivo on lipopolysaccharide (LPS)-induced inflammation models. Results: sHDLs composed with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (22A-DMPC) most effectively neutralizes LPS, inhibits toll-like receptor 4 recruitment into lipid rafts, suppresses nuclear factor κB signaling and promotes activating transcription factor 3 activating. The lethal endotoxemia animal model showed the protective effects of 22A-DMPC. Conclusion: Phospholipid components affect the stability and fluidity of nanodiscs, impacting the anti-septic efficacy of sHDLs. 22A-DMPC presents the strongest LPS binding and anti-inflammatory effects in vitro and in vivo, suggesting a potential sepsis treatment.

HDL inhibits pancreatic acinar cell NLRP3 inflammasome activation and protect against acinar cell pyroptosis in acute pancreatitis

BACKGROUND AND PURPOSE

Recent clinical studies have shown that serum high-density lipoprotein (HDL) levels are correlated with acute pancreatitis (AP) severity. We aimed to investigate the role of HDL in pancreatic necrosis in AP.

EXPERIMENTAL APPROACH

ApoA-I is the main constitution and function component of HDL. The roles of healthy human-derived HDL and apoA-I mimic peptide D4F were demonstrated in AP models in vivo and in vitro. Constitutive Apoa1 genetic inhibition on AP severity, especially pancreatic necrosis was assessed in both caerulein and sodium taurocholate induced mouse AP models. In addition, constitutive (Casp1-/-) and acinar cell conditional (Pdx1CreNlrp3Δ/Δ and Pdx1CreGsdmdΔ/Δ) mice were used to explore the effects of HDL on acinar cell pyroptosis in AP.

KEY RESULTS

Apoa1 knockout dramatically aggravated pancreatic necrosis. Human-derived HDL protected against acinar cell death in vivo and in vitro. We found that mimic peptide D4F also protected against AP very well. Constitutive Casp1 or acinar cell-conditional Nlrp3 and Gsdmd genetic inhibition could counteract the protective effects of HDL, implying HDL may exert beneficial effects on AP through inhibiting acinar cell pyroptosis.

CONCLUSION AND IMPLICATIONS

This work demonstrates the protective role of HDL and apoA-I in AP pathology, potentially driven by the inhibition of NLRP3 inflammasome signaling and acinar cell pyroptosis. Mimic peptides have promise as specific therapies for AP.

Biomimetic nanomedicines for precise atherosclerosis theranostics

Atherosclerosis (AS) is a leading cause of the life-threatening cardiovascular disease (CVD), creating an urgent need for efficient, biocompatible therapeutics for diagnosis and treatment. Biomimetic nanomedicines (bNMs) are moving closer to fulfilling this need, pushing back the frontier of nano-based drug delivery systems design. This review seeks to outline how these nanomedicines (NMs) might work to diagnose and treat atherosclerosis, to trace the trajectory of their development to date and in the coming years, and to provide a foundation for further discussion about atherosclerotic theranostics.

Nanotechnology in coronary heart disease

Coronary heart disease (CHD) is one of the major causes of death and disability worldwide, especially in low- and middle-income countries and among older populations. Conventional diagnostic and therapeutic approaches have limitations such as low sensitivity, high cost and side effects. Nanotechnology offers promising alternative strategies for the diagnosis and treatment of CHD by exploiting the unique properties of nanomaterials. In this review, we use bibliometric analysis to identify research hotspots in the application of nanotechnology in CHD and provide a comprehensive overview of the current state of the art. Nanomaterials with enhanced imaging and biosensing capabilities can improve the early detection of CHD through advanced contrast agents and high-resolution imaging techniques. Moreover, nanomaterials can facilitate targeted drug delivery, tissue engineering and modulation of inflammation and oxidative stress, thus addressing multiple aspects of CHD pathophysiology. We discuss the application of nanotechnology in CHD diagnosis (imaging and sensors) and treatment (regulation of macrophages, cardiac repair, anti-oxidative stress), and provide insights into future research directions and clinical translation. This review serves as a valuable resource for researchers and clinicians seeking to harness the potential of nanotechnology in the management of CHD. STATEMENT OF SIGNIFICANCE: Coronary heart disease (CHD) is the one of leading cause of death and disability worldwide. Nanotechnology offers new strategies for diagnosing and treating CHD by exploiting the unique properties of nanomaterials. This review uses bibliometric analysis to uncover research trends in the use of nanotechnology for CHD. We discuss the potential of nanomaterials for early CHD detection through advanced imaging and biosensing, targeted drug delivery, tissue engineering, and modulation of inflammation and oxidative stress. We also offer insights into future research directions and potential clinical applications. This work aims to guide researchers and clinicians in leveraging nanotechnology to improve CHD patient outcomes and quality of life.

Characteristics and evaluation of atherosclerotic plaques: an overview of state-of-the-art techniques

Atherosclerosis is an important cause of cerebrovascular and cardiovascular disease (CVD). Lipid infiltration, inflammation, and altered vascular stress are the critical mechanisms that cause atherosclerotic plaque formation. The hallmarks of the progression of atherosclerosis include plaque ulceration, rupture, neovascularization, and intraplaque hemorrhage, all of which are closely associated with the occurrence of CVD. Assessing the severity of atherosclerosis and plaque vulnerability is crucial for the prevention and treatment of CVD. Integrating imaging techniques for evaluating the characteristics of atherosclerotic plaques with computer simulations yields insights into plaque inflammation levels, spatial morphology, and intravascular stress distribution, resulting in a more realistic and accurate estimation of plaque state. Here, we review the characteristics and advancing techniques used to analyze intracranial and extracranial atherosclerotic plaques to provide a comprehensive understanding of atheroma.

Liver X receptors: From pharmacology to nanoparticle-based drug delivery

Liver X receptors (LXRs) are master regulators of various biological processes, including metabolism, inflammation, development, and reproduction. As well-known nuclear oxysterol receptors of the nuclear receptor (NR) family, LXRs have two homologous subtypes, LXRα (NR1H3) and LXRβ (NR1H2). Since the mid-1990s, numerous LXR-targeted drugs have been designed to treat diseases such as atherosclerosis, systemic lupus erythematosus, and cancer. These modulators include agonists and antagonists, and the selectivity of them have been development from diverse aspects, including subtype-specific, cell-specific, tissue-specific types. Meanwhile, advanced delivery systems are also exploreed to facilitate the application of LXR drugs in clinical setting. One of the most promising delivery systems involves the use of nanoparticles and is expected to increase the clinical potential of LXR modulators. This review discusses our current understanding of LXR biology and pharmacology, focusing on the development of modulators for LXRα and/or LXRβ, and the nanoparticle-based delivery systems for promising LXR modulators with potential for use as drugs.

Nanomedicines for cardiovascular disease

The leading cause of death in the world, cardiovascular disease (CVD), remains a formidable condition for researchers, clinicians and patients alike. CVD comprises a broad collection of diseases spanning the heart, the vasculature and the blood that runs through and interconnects them. Limitations in CVD therapeutic and diagnostic landscapes have generated excitement for advances in nanomedicine, a field focused on improving patient outcomes through transformative therapies, imaging agents and ex vivo diagnostics. CVD nanomedicines are fundamentally shaped by their intended clinical application, including (1) cardiac or heart-related biomaterials, which can be functionally (for example, mechanically, immunologically, electrically) improved by incorporating nanomaterials; (2) the vasculature, involving systemically injected nanotherapeutics and imaging nanodiagnostics, nano-enabled biomaterials or tissue-nanoengineered solutions; and (3) improving the sensitivity and/or specificity of ex vivo diagnostic devices for patient samples. While immunotherapy has developed into a key pillar of oncology in the past dozen years, CVD immunotherapy and immunoimaging are recently emergent and likely to factor substantially in CVD management in the coming decade. The nanomaterials in CVD-related clinical trials and many promising preclinical strategies indicate that nanomedicine is on the cusp of greatly impacting patients with CVD. Here we review these recent advances, highlighting key clinical opportunities in the rapidly emerging field of CVD nanomedicine.

Targeting Theranostics of Atherosclerosis by Dual-Responsive Nanoplatform via Photoacoustic Imaging and Three-In-One Integrated Lipid Management

Atherosclerosis, as a life-threatening cardiovascular disease with chronic inflammation and abnormal lipid enrichment, is often difficult to treat timely due to the lack of obvious symptoms. In this work, a theranostic nanoplatform is constructed for the noninvasive in vivo diagnosis, plaque-formation inhibition, and the lesion reversal of atherosclerosis. A three-in-one therapeutic complex is constructed and packaged along with a polymeric photoacoustic probe into nanoparticles named as PLCDP@PMH, which indicates an atherosclerosis-targeting accumulation and a reactive oxygen species (ROS)/matrix metalloproteinase (MMP) dual-responsive degradation. The photoacoustic probe suggests a lesion-specific imaging on atherosclerotic mice with an accurate and distinct recognition of plaques. At the same time, the three-in-one complex performs an integrated lipid management through the inhibition of macrophages M1-polarization, liver X receptor (LXR)-mediated up-regulation of ATP-binding cassette transporter A1/G1 (ABCA1/G1) and the cyclodextrin-assisted lipid dissolution, which lead to the reduced lipid uptake, enhanced lipid efflux, and actuated lipid removal. The in vivo evaluations reveal that PLCDP@PMH can suppress the lesion progression and further reverse the formed plaques under a diet without high fat. Hence, PLCDP@PMH provides a candidate for the theranostics of early-stage atherosclerosis and delivers an impressive potential on the reversal of formed atherosclerotic lesions.

A green-inspired method to prepare non-split high-density lipoprotein (HDL) carrier with anti-dysfunctional activities superior to reconstituted HDL

Numerous studies have demonstrated that dysfunctional high-density lipoprotein (HDL), especially oxidized HDL (OxHDL), could generate multifaceted in vivo proatherogenic effects that run counter to the antiatherogenic activities of HDL. It thereby reminded us that the in vitro reconstituted HDL (rHDL) might encountered with oxidation-induced dysfunction. Accordingly, a green-inspired method was employed to recycle non-split HDL from human plasma fraction IV. Then it was compared with rHDL formulated by an ethanol-injection method in terms of physicochemical properties and anti-dysfunctional activities. Results exhibited that rHDL oxidation extent exceeded that of non-split HDL evidenced by higher malondialdehy content, weaker inhibition on low-density lipoprotein (LDL) oxidation and more superoxide anion. The reserved paraoxonase-1 activity on non-split HDL could partially explain for above experimental results. In the targeted transport mechanism experiment, upon SR-BI receptor inhibition and/or CD36 receptor blockage, the almost unchanged non-split HDL uptake in lipid-laden macrophage indicated its negligible oxidation modification profile with regard to rHDL again. Furthermore, compared to rHDL, better macrophage biofunctions were observed for non-split HDL as illustrated by accelerated cholesterol efflux, inhibited oxidized LDL uptake and lessened cellular lipid accumulation. Along with decreased ROS secretion, obviously weakened oxidative stress damage was also detected under treatment with non-split HDL. More importantly, foam cells with non-split HDL-intervention inspired an enhanced inflammation repression and apoptosis inhibition effect. Collectively, the anti-dysfunctional activities of non-split HDL make it suitable as a potential nanocarrier platform for cardiovascular drug payload and delivery.

Targeting macrophages in atherosclerosis using nanocarriers loaded with liver X receptor agonists: A narrow review

Macrophages are involved in the whole process of atherosclerosis, which is characterized by accumulation of lipid and inflammation. Presently, clinically used lipid-lowering drugs cannot completely retard the progress of atherosclerosis. Liver X receptor (LXR) plays a key role in regulation of lipid metabolism and inflammation. Accumulating evidence have demonstrated that synthetic LXR agonists can significantly retard the development of atherosclerosis. However, these agonists induce sever hypertriglyceridemia and liver steatosis. These side effects have greatly limited their potential application for therapy of atherosclerosis. The rapid development of drug delivery system makes it possible to delivery interested drugs to special organs or cells using nanocarriers. Macrophages express various receptors which can recognize and ingest specially modified nanocarriers loaded with LXR agonists. In the past decades, a great progress has been made in this field. These macrophage-targeted nanocarriers loaded with LXR agonists are found to decrease atherosclerosis by reducing cholesterol accumulation and inflammatory reactions. Of important, these nanocarriers can alleviate side effects of LXR agonists. In this article, we briefly review the roles of macrophages in atherosclerosis, mechanisms of action of LXR agonists, and focus on the advances of macrophage-targeted nanocarriers loaded with LXR agonists. This work may promote the potential clinical application of these nanocarriers.

Development of activated endothelial targeted high-density lipoprotein nanoparticles

Endothelial inflammation is an important pathophysiological driving force in various acute and chronic inflammatory diseases. High-density lipoproteins (HDLs) play critical roles in regulating endothelial functions and resolving endothelial inflammation. In the present study, we developed synthetic HDLs (sHDLs) which actively target inflamed endothelium through conjugating vascular cell adhesion protein 1 (VCAM-1) specific VHPK peptide. The active targeting of VHPK-sHDLs was confirmed in vitro on TNF-α activated endothelial cells. VHPK-sHDLs presented potent anti-inflammatory efficacies in vitro through the reduction of proinflammatory cytokine production and inhibition of leukocyte adhesion to activated endothelium. VHPK-sHDLs showed increased binding on inflamed vessels and alleviated LPS-induced lung inflammation in vivo. The activated endothelium-targeted sHDLs may be further optimized to resolve endothelial inflammation in various inflammatory diseases.

Synthetic high-density lipoprotein nanoparticles delivering rapamycin for the treatment of age-related macular degeneration

Synthetic high-density lipoprotein (sHDL) and rapamycin (Rap) have both been shown to be potential treatments for age-related macular degeneration (AMD). The low aqueous solubility of Rap, however, limits its therapeutic utility. Here we used an Apolipoprotein A-I mimetic peptide and phospholipid-based sHDL for the intravitreal delivery of Rap. By incorporation of Rap in sHDL nanoparticles (sHDL-Rap), we achieve 125-fold increase in drug aqueous concentration. When applied in vitro to retinal pigment epithelium cells, sHDL-Rap exhibited the abilities to efflux cholesterol, neutralize endotoxin, and suppress NF-κB activation. As an mTOR inhibitor, Rap induced autophagy and inhibited NF-κB-mediated pro-inflammatory signaling. Additionally, a greater reduction in lipofuscin accumulation and increased anti-inflammatory effects were achieved by sHDL-Rap relative to free drug or sHDL alone. In vivo studies demonstrated that sHDL reached the target retina pigment epithelium (RPE) layer following intravitreal administration in rats. These results suggest that sHDL-Rap holds potential as a treatment for AMD.

Isochlorogenic Acid C Alleviates High-Fat Diet-Induced Hyperlipemia by Promoting Cholesterol Reverse Transport

Background: Promoting cholesterol reverse transport (RCT) has been proven to be a promising hyperlipidemia therapy since it is more effective for the treatment of atherosclerosis (AS) caused by hyperlipidemia. Liver X receptor (LXR) agonists can accelerate RCT, but most of them trigger undesirable liver steatosis due to the activation of liver LXRα.

Aim: We aim to figure out whether isochlorogenic acid C (ICAC) facilitates RCT without causing hepatic steatosis.

Methods:In vitro study, we established foam macrophages and macrophages with loaded NBD-cholesterol models to investigate the competence of RCT promoting ICAC. RT-qPCR and Western blot were used to verify ICAC’s regulation of RCT and NF-κB inflammatory pathways. In this in vivo study, male 6-week-old C57BL/6 mice were fed a high-fat diet (HFD) to investigate ICAC’s anti-hyperlipidemic effect and its functions in regulating RCT. The anti-hyperlipidemic effect of ICAC was evaluated by blood and liver lipid levels, liver hematoxylin, oil red o staining, and liver coefficient. Finally, mRNA levels of genes involved in RCT and inflammation pathways in the liver and intestine were detected by RT-qPCR.

Results: ICAC prevented macrophages from foaming by up-regulating the LXRα mediated RCT pathway and down-regulating expression of the cholesterol absorption genes LDLR and CD36, as well as suppressing iNOS, COX2, and IL-1β inflammatory factors. In HFD-fed mice, ICAC significantly lowered the lipid level both in the serum and the liver. Mechanistic studies showed that ICAC strengthened the RCT pathway in the liver and intestine but didn’t affect liver LXRα. Furthermore, ICAC impeded both adipogenesis and the inflammatory response in the liver.

Conclusion: ICAC accelerated RCT without affecting liver LXRα, thus resulting in a lipid-lowering effect without increasing liver adipogenesis. Our results indicated that ICAC could be a new RCT promoter for hyperlipidemia treatment without causing liver steatosis.

Molecular ZIP codes in targeted drug delivery

The term "molecular ZIP (or area) codes" refers to an originally hypothetical system of cell adhesion molecules that would control cell trafficking in the body. Subsequent discovery of the integrins, cadherins, and other cell adhesion molecules confirmed this hypothesis. The recognition system encompassing integrins and their ligands came particularly close to fulfilling the original ZIP code hypothesis, as multiple integrins with closely related specificities mediate cell adhesion by binding to an RGD or related sequence in various extracellular matrix proteins. Diseased tissues have their own molecular addresses that, although not necessarily involved in cell trafficking, can be made use of in targeted drug delivery. This article discusses the molecular basis of ZIP codes and the extensive effort under way to harness them for drug delivery purposes.

Nanodisc delivery of liver X receptor agonist for the treatment of diabetic nephropathy

Dyslipidemia is recognized to be an important contributor to the progression of diabetic nephropathy (DN), leading to lipoprotein dysregulation, excessive mesangium expansion as well as inflammation in the glomeruli. Thus, dual targeting of abnormal cholesterol metabolism and inflammatory responses of mesangial cells represents an alternative approach for DN treatment. Herein, we sought to develop a renal-targeting therapeutic strategy for diabetic nephropathy by modifying synthetic high-density lipoprotein (sHDL) nanodiscs with a kidney targeting ligand (KT peptide) and encapsulating a liver X receptor (LXR) agonist in the modified sHDL. LXR agonists delivered by sHDL can facilitate the removal of excessive lipids from mesangial cells, ameliorate inflammation and restore normal renal function. Overall, our data suggests that our optimized KT-targeted sHDL/TO nanodiscs (KT-sHDL/TO) generate potent therapeutic efficacy not only by more efficient cholesterol efflux, but also by suppressing mesangial cell proliferation. Most importantly, in a DN murine model, KT-sHDL/TO ameliorated dyslipidemia and inflammation superior to blank sHDL and non-targeting sHDL/TO formulations, showing promise for future clinical translation in DN treatment.

The Functional Role of Lipoproteins in Atherosclerosis: Novel Directions for Diagnosis and Targeting Therapy

Dyslipidemia, characterized by a high level of lipids (cholesterol, triglycerides, or both), can increase the risk of developing and progressing atherosclerosis. As atherosclerosis progresses, the number and severity of aterial plagues increases with greater risk of myocardial infarction, a major contributor to cardiovascular mortality. Atherosclerosis progresses in four phases, namely endothelial dysfunction, fatty streak formation, lesion progression and plaque rupture, and eventually thrombosis and arterial obstruction. With greater understanding of the pathological processes underlying atherosclerosis, researchers have identified that lipoproteins play a significant role in the development of atherosclerosis. In particular, apolipoprotein B (apoB)-containing lipoproteins have been shown to associate with atherosclerosis. Oxidized low-density lipoproteins (ox-LDLs) also contribute to the progression of atherosclerosis whereas high-density lipoproteins (HDL) contribute to the removal of cholesterol from macrophages thereby inhibiting the formation of foam cells. Given these known associations, lipoproteins may have potential as biomarkers for predicting risk associated with atherosclerotic plaques or may be targets as novel therapeutic agents. As such, the rapid development of drugs targeting lipoprotein metabolism may lead to novel treatments for atherosclerosis. A comprehensive review of lipoprotein function and their role in atherosclerosis, along with the latest development of lipoprotein targeted treatment, is timely. This review focuses on the functions of different lipoproteins and their involvement in atherosclerosis. Further, diagnostic and therapeutic potential are highlighted giving insight into novel lipoprotein-targetted approaches to treat atherosclerosis.

Intercepting IRE1 kinase-FMRP signaling prevents atherosclerosis progression

Fragile X Mental Retardation protein (FMRP), widely known for its role in hereditary intellectual disability, is an RNA‐binding protein (RBP) that controls translation of select mRNAs. We discovered that endoplasmic reticulum (ER) stress induces phosphorylation of FMRP on a site that is known to enhance translation inhibition of FMRP‐bound mRNAs. We show ER stress‐induced activation of Inositol requiring enzyme‐1 (IRE1), an ER‐resident stress‐sensing kinase/endoribonuclease, leads to FMRP phosphorylation and to suppression of macrophage cholesterol efflux and apoptotic cell clearance (efferocytosis). Conversely, FMRP deficiency and pharmacological inhibition of IRE1 kinase activity enhances cholesterol efflux and efferocytosis, reducing atherosclerosis in mice. Our results provide mechanistic insights into how ER stress‐induced IRE1 kinase activity contributes to macrophage cholesterol homeostasis and suggests IRE1 inhibition as a promising new way to counteract atherosclerosis.

Macrophage-targeted nanomedicine for the diagnosis and treatment of atherosclerosis

Nanotechnology could improve our understanding of the pathophysiology of atherosclerosis and contribute to the development of novel diagnostic and therapeutic strategies to further reduce the risk of cardiovascular disease. Macrophages have key roles in atherosclerosis progression and, therefore, macrophage-associated pathological processes are important targets for both diagnostic imaging and novel therapies for atherosclerosis. In this Review, we highlight efforts in the past two decades to develop imaging techniques and to therapeutically manipulate macrophages in atherosclerotic plaques with the use of rationally designed nanoparticles. We review the latest progress in nanoparticle-based imaging modalities that can specifically target macrophages. Using novel molecular imaging technology, these modalities enable the identification of advanced atherosclerotic plaques and the assessment of the therapeutic efficacy of medical interventions. Additionally, we provide novel perspectives on how macrophage-targeting nanoparticles can deliver a broad range of therapeutic payloads to atherosclerotic lesions. These nanoparticles can suppress pro-atherogenic macrophage processes, leading to improved resolution of inflammation and stabilization of plaques. Finally, we propose future opportunities for novel diagnostic and therapeutic strategies and provide solutions to challenges in this area for the purpose of accelerating the clinical translation of nanomedicine for the treatment of atherosclerotic vascular disease.

Associations of Monocytes and the Monocyte/High-Density Lipoprotein Ratio With Extracranial and Intracranial Atherosclerotic Stenosis

Background: Although the monocyte/high-density lipoprotein ratio (MHR) has been shown to be a potential marker of inflammatory of cardiovascular and cerebrovascular diseases, there are few studies on its relationships with the degree of intracranial and extracranial atherosclerotic stenosis and the stenosis distribution.

Methods: In total, 271 patients were admitted for digital subtraction angiography (DSA) examination and were classified into a non-stenosis group and a stenosis group. (1) The two groups were compared and the arteries were categorized according to the degree of intracranial or extracranial atherosclerotic stenosis (if ≥two branches were stenotic, the artery with the most severe stenosis was used). (2) Clinical baseline data and laboratory indexes of patients grouped according to stenosis location (intracranial vs. extracranial) were collected.

Results: (1) MHR × 10² [odds ratio (OR) = 1.119, p < 0.001], age (OR = 1.057, p = 0.007), and lymphocyte count (OR = 0.273, p = 0.002) significantly affected the presence of cerebral atherosclerotic stenosis, with an MHR area of 0.82 under the receiver operating characteristic (ROC) curve (AUC) and an optimal diagnostic value of 0.486. Analyses of the moderate, mild, and severe stenosis groups showed that MHR × 10² (OR = 1.07, p < 0.001) significantly affected the severity of stenosis in patients. (2) In the analysis of stenosis at different sites, the rate of extracranial artery stenosis in patients who smoked (OR = 3.86, p = 0.023) and had a reduced lymphocyte level (OR = 0.202, p = 0.001) was remarkably greater than that in patients who smoked (OR = 3.86, p = 0.023). With increasing age, the rate of extracranial artery stenosis raised sharply. With the increase in the MHR level, the stenosis rate of each group was highly greater than that of the non-stenosis group.

Conclusion: The MHR has a predictive value for the diagnosis of extracranial and intracranial atherosclerotic stenosis and is correlated with the degree and distribution of stenosis.

Trial Registration: Clinical Medical Research Center Project of Qinghai Province (2017-SF-L1). Qinghai Provincial Health Commission Project (Grant #2020-wjzdx-29).

Phospholipid nanoparticles: Therapeutic potentials against atherosclerosis via reducing cholesterol crystals and inhibiting inflammation

Background

Atherosclerosis-related cardiovascular diseases (CVDs) are the leading cause of mortality worldwide. Cholesterol crystals (CCs) induce inflammation in atherosclerosis and are associated with unstable plaques and poor prognosis, but no drug can remove CCs in the clinic currently.

Methods

We generated a phospholipid-based and high-density lipoprotein (HDL)-like nanoparticle, miNano, and determined CC-dissolving capacity, cholesterol efflux property, and anti-inflammation effects of miNano in vitro. Both normal C57BL/6J and Apoe-deficient mice were used to explore the accumulation of miNano in atherosclerotic plaques. The efficacy and safety of miNano administration to treat atherosclerosis were evaluated in the Ldlr-deficient atherosclerosis model. The CC-dissolving capacity of miNano was also detected using human atherosclerotic plaques ex vivo.

Findings

We found that miNano bound to and dissolved CCs efficiently in vitro, and miNano accumulated in atherosclerotic plaques, co-localized with CCs and macrophages in vivo. Administration of miNano inhibited atherosclerosis and improved plaque stability by reducing CCs and macrophages in Ldlr-deficient mice with favorable safety profiles. In macrophages, miNano prevented foam cell formation by enhancing cholesterol efflux and suppressed inflammatory responses via inhibiting TLR4-NF-κB pathway. Finally, in an ex vivo experiment, miNano effectively dissolved CCs in human aortic atherosclerotic plaques.

Interpretation

Together, our work finds that phospholipid-based and HDL-like nanoparticle, miNano, has the potential to treat atherosclerosis by targeting CCs and stabilizing plaques.

Funding

This work was supported by the National Institutes of Health HL134569, HL109916, HL136231, and HL137214 to Y.E.C, HL138139 to J.Z., R21NS111191 to A.S., by the American Heart Association 15SDG24470155, Grant Awards (U068144 from Bio-interfaces and G024404 from M-BRISC) at the University of Michigan to Y.G., by the American Heart Association 19PRE34400017 and Rackham Helen Wu award to M.Y., NIH T32 GM07767 to K. H., Barbour Fellowship to D.L.

Nanotechnology for Targeted Therapy of Atherosclerosis

Atherosclerosis is the major cause of heart attack and stroke that are the leading causes of death in the world. Nanomedicine is a powerful tool that can be engineered to target atherosclerotic plaques for therapeutic and diagnosis purposes. In this review, advances in designing nanoparticles with therapeutic effects on atherosclerotic plaques known as atheroprotective nanomedicine have been summarized to stimulate further development and future translation.

Lipids and Lipid Derivatives for RNA Delivery

RNA-based therapeutics have shown great promise in treating a broad spectrum of diseases through various mechanisms including knockdown of pathological genes, expression of therapeutic proteins, and programmed gene editing. Due to the inherent instability and negative-charges of RNA molecules, RNA-based therapeutics can make the most use of delivery systems to overcome biological barriers and to release the RNA payload into the cytosol. Among different types of delivery systems, lipid-based RNA delivery systems, particularly lipid nanoparticles (LNPs), have been extensively studied due to their unique properties, such as simple chemical synthesis of lipid components, scalable manufacturing processes of LNPs, and wide packaging capability. LNPs represent the most widely used delivery systems for RNA-based therapeutics, as evidenced by the clinical approvals of three LNP-RNA formulations, patisiran, BNT162b2, and mRNA-1273. This review covers recent advances of lipids, lipid derivatives, and lipid-derived macromolecules used in RNA delivery over the past several decades. We focus mainly on their chemical structures, synthetic routes, characterization, formulation methods, and structure-activity relationships. We also briefly describe the current status of representative preclinical studies and clinical trials and highlight future opportunities and challenges.

HDL and reverse cholesterol transport in humans and animals: Lessons from pre-clinical models and clinical studies

The ability to accept cholesterol from cells and to promote reverse cholesterol transport (RCT) represents the best characterized antiatherogenic function of HDL. Studies carried out in animal models have unraveled the multiple mechanisms by which these lipoproteins drive cholesterol efflux from macrophages and cholesterol uptake to the liver. Moreover, the influence of HDL composition and the role of lipid transporters have been clarified by using suitable transgenic models or through experimental design employing pharmacological or nutritional interventions. Cholesterol efflux capacity (CEC), an in vitro assay developed to offer a measure of the first step of RCT, has been shown to associate with cardiovascular risk in several human cohorts, supporting the atheroprotective role of RCT in humans as well. However, negative data in other cohorts have raised concerns on the validity of this biomarker. In this review we will present the most relevant data documenting the role of HDL in RCT, as assessed in classical or innovative methodological approaches.

Macrophages in Atherosclerosis, First or Second Row Players?

Macrophages represent a cell type that has been widely described in the context of atherosclerosis since the earliest studies in the 17th century. Their role has long been considered to be preponderant in the onset and aggravation of atherosclerosis, in particular by participating in the establishment of a chronic inflammatory state by the release of pro-inflammatory cytokines and by uncontrolled engorgement of lipids resulting in the formation of foam cells and later of the necrotic core. However, recent evidence from mouse models using an elegant technique of tracing vascular smooth muscle cells (VSMCs) during plaque development revealed that resident VSMCs display impressive plastic properties in response to an arterial injury, allowing them to switch into different cell types within the plaque, including mesenchymal-like cells, macrophage-like cells and osteochondrogenic-like cells. In this review, we oppose the arguments in favor or against the influence of macrophages versus VSMCs in all stages of atherosclerosis including pre-atherosclerosis, formation of lipid-rich foam cells, development of the necrotic core and the fibrous cap as well as calcification and rupture of the plaque. We also analyze the relevance of animal models for the investigation of the pathophysiological mechanisms of atherosclerosis in humans, and discuss potential therapeutic strategies targeting either VSMCs or macrophage to prevent the development of cardiovascular events. Overall, although major findings have been made from animal models, efforts are still needed to better understand and therefore prevent the development of atherosclerotic plaques in humans.

Self-Assembled Peptide Amphiphile Nanofibers for Controlled Therapeutic Delivery to the Atherosclerotic Niche

Atherosclerotic plaque remains the leading contributor to cardiovascular disease and requires invasive surgical procedures for its removal. Nanomedicine offers a minimally invasive approach to alleviate plaque burden by targeted therapeutic delivery. However, nanocarriers are limited without the ability to sense and respond to the diseased microenvironment. In this study, targeted self-assembled peptide amphiphile (PA) nanofibers were developed that cleave in response to biochemical cues expressed in atherosclerotic lesions-reactive oxygen species (ROS) and intracellular glutathione-to deliver a liver X receptor agonist (LXR) to enhance macrophage cholesterol efflux. The PAs released LXR in response to physiological levels of ROS and reducing agents and could be co-assembled with plaque-targeting PAs to form nanofibers. The resulting LXR PA nanofibers promoted cholesterol efflux from macrophages in vitro as well as LXR alone and with lower cytotoxicity. Further, the ApoA1-LXR PA nanofibers targeted plaque within an atherosclerotic mouse model in vivo and activated ATP-binding cassette A1 (ABCA1) expression as well as LXR alone with reduced liver toxicity. Taken together, these results demonstrate the potential of self-assembled PA nanofibers for controlled therapeutic delivery to the atherosclerotic niche.

Efficacy and Safety of High-Density Lipoprotein/Apolipoprotein A1 Replacement Therapy in Humans and Mice With Atherosclerosis: A Systematic Review and Meta-Analysis

Background: Although elevation of HDL-C levels by pharmaceutical drugs have no benefit of cardiovascular endpoint, the effect of high-density lipoprotein/apolipoprotein A1 (HDL/apoA-1) replacement therapy on atherosclerosis is controversial. The current meta-analysis analyzed the effects of HDL/apoA-1 replacement therapies on atherosclerotic lesions both in humans and mice.

Methods: The PubMed, Cochrane Library, Web of Science, and EMBASE databases were searched through June 6, 2020. The methodological quality of the human studies was assessed using Review Manager (RevMan, version 5.3.). The methodological quality of the mouse studies was assessed using a stair list. STATA (version 14.0) was used to perform all statistical analyses.

Results: Fifteen randomized controlled human trials and 17 animal studies were included. The pooled results showed that HDL/apoA-1 replacement therapy use did not significantly decrease the percent atheroma volume (p = 0.766) or total atheroma volume (p = 0.510) in acute coronary syndrome (ACS) patients (N = 754). However, HDL/apoA-1 replacement therapies were significantly associated with the final percent lesion area, final lesion area, and changes in lesion area (SMD, −1.75; 95% CI: −2.21~-1.29, p = 0.000; SMD, −0.78; 95% CI: −1.18~-0.38, p = 0.000; SMD: −2.06; 95% CI, −3.92~-0.2, p = 0.03, respectively) in mice.

Conclusions: HDL/apoA-1 replacement therapies are safe but do not significantly improve arterial atheroma volume in humans. The results in animals suggest that HDL/apoA-1 replacement therapies decrease the lesion area. Additional studies are needed to investigate and explain the differences in HDL/apoA-1 replacement therapy efficacies between humans and animals.

Trial registration number: Human pooled analysis: PROSPERO, CRD42020210772. prospectively registered.

(r)HDL in theranostics: how do we apply HDL's biology for precision medicine in atherosclerosis management?

High-density lipoproteins (HDL) are key players in cholesterol metabolism homeostasis since they are responsible for transporting excess cholesterol from peripheral tissues to the liver. Imbalance in this process, due to either excessive accumulation or impaired clearance, results in net cholesterol accumulation and increases the risk of cardiovascular disease (CVD). Therefore, significant effort has been focused on the development of therapeutic tools capable of either directly or indirectly enhancing HDL-guided reverse cholesterol transport (RCT). More recently, in light of the emergence of precision nanomedicine, there has been renewed research interest in attempting to take advantage of the development of advanced recombinant HDL (rHDL) for both therapeutic and diagnostic purposes. In this review, we provide an update on the different approaches that have been developed using rHDL, focusing on the rHDL production methodology and rHDL applications in theranostics. We also compile a series of examples highlighting potential future perspectives in the field.

Targeting macrophages using nanoparticles: a potential therapeutic strategy for atherosclerosis

Atherosclerosis is one of the leading causes of vascular diseases, with high morbidity and mortality worldwide. Macrophages play a critical role in the development and local inflammatory responses of atherosclerosis, contributing to plaque rupture and thrombosis. Considering their central roles, macrophages have gained considerable attention as a therapeutic target to attenuate atherosclerotic progression and stabilize existing plaques. Nanoparticle-based delivery systems further provide possibilities to selectively and effectively deliver therapeutic agents into intraplaque macrophages. Although challenges are numerous and clinical application is still distant, the design and development of macrophage-targeting nanoparticles will generate new knowledge and experiences to improve therapeutic outcomes and minimize toxicity. Hence, the review aims to discuss various strategies for macrophage modulation and the development and evaluation of macrophage targeting nanomedicines for anti-atherosclerosis.

Recent advances in nanomaterials for therapy and diagnosis for atherosclerosis

Atherosclerosis is a chronic inflammatory disease driven by lipid accumulation in arteries, leading to narrowing and thrombosis. It affects the heart, brain, and peripheral vessels and is the leading cause of mortality in the United States. Researchers have strived to design nanomaterials of various functions, ranging from non-invasive imaging contrast agents, targeted therapeutic delivery systems to multifunctional nanoagents able to target, diagnose, and treat atherosclerosis. Therefore, this review aims to summarize recent progress (2017-now) in the development of nanomaterials and their applications to improve atherosclerosis diagnosis and therapy during the preclinical and clinical stages of the disease.

Synthetic high-density lipoproteins delivering liver X receptor agonist prevent atherogenesis by enhancing reverse cholesterol transport

Liver X nuclear receptor (LXR) agonists are promising anti-atherosclerotic agents that increase the expression of cholesterol transporters on atheroma macrophages leading to increased efflux of cholesterol to endogenous high-density lipoprotein (HDL) acceptors. HDL subsequently delivers effluxed cholesterol to the liver by the process of reverse cholesterol transport, resulting in reduction of atherosclerotic plaques. However, LXR agonists administration triggers undesirable liver steatosis and hypertriglyceridemia due to increased fatty acid and sterol synthesis. LXR-induced liver toxicity, poor drug aqueous solubility and low levels of endogenous HDL acceptors in target patient populations limit the clinical translation of LXR agonists. Here, we propose a dual-antiatherogenic strategy for administration of the LXR agonist, T0901317 (T1317), by encapsulating in synthetic HDL (sHDL) nanoparticles. sHDL had been clinically proven to serve as cholesterol acceptors, resulting in plaque reduction in atherosclerosis patients. In addition, the hydrophobic core and endogenous atheroma-targeting ability of sHDL allow for encapsulation of water-insoluble drugs and their subsequent delivery to atheroma. Several compositions of sHDL were tested to optimize both T1317 encapsulation efficiency and ability of T1317-sHDL to efflux cholesterol. Optimized T1317-sHDL exhibited more efficient cholesterol efflux from macrophages and enhanced atheroma-targeting relative to free drug. Most importantly, in an apolipoprotein E deficient (ApoE-/-) atherosclerosis progression murine model, T1317-sHDL showed superior inhibition of atherogenesis and reduced hypertriglyceridemia side effects in comparison to the free drug and blank sHDL. The T1317-sHDL pharmacological efficacy was observed at doses lower than those previously described for LXR agents, which may have additional safety benefits. In addition, the established clinical manufacturing, safety and efficacy of blank sHDL nanoparticles used in this study could facilitate future clinical translation of LXR-loaded sHDLs.

Synergetic Effect of rHDL and LXR Agonist on Reduction of Atherosclerosis in Mice

High-density lipoproteins (HDLs) are unique in that they play an important role in the reverse cholesterol transport process. However, reconstituted HDL (rHDL) infusions have demonstrated limited beneficial effect in clinical practice. This is perhaps a consequence of the limited cholesterol efflux abilities of atheroma macrophages due to decreased expression of cholesterol transporters in advanced atheromas and following rHDL infusion treatment. Thus, we propose that a combination therapy of rHDL and a liver X receptor (LXR) agonist could maximize the therapeutic benefit of rHDL by upregulating ATP-binding cassette transporters A-1 (ABCA1) and ATP-binding cassette transporter G-1 (ABCG1), and enhancing cholesterol efflux to rHDL. In macrophages, rHDL downregulated the expression of ABCA1/G1 in a dose- and rHDL composition-dependent manner. Although LXR agonist, T0901317 (T1317), upregulated the expression of ABCA1 and ABCG1, the drug itself did not have any effect on cholesterol efflux (6.6 ± 0.5%) while the combination of rHDL and T1317 exhibited enhanced cholesterol efflux from [³H]-cholesterol loaded J774A.1 macrophages (23.3 ± 1.3%). Treatment with rHDL + T1317 significantly reduced the area of aortic plaque in ApoE^-/- mice compared to PBS treated control animals (24.16 ± 1.42% vs. 31.59 ± 1.93%, p < 0.001), while neither rHDL nor T1317 treatment alone had a significant effect. Together, we show that rHDL paired with an LXR agonist can induce a synergetic effect in reducing atheroma burden. This synergy could lead to lower overall effective dose for both drugs, potentially overcoming the existing barriers in clinical development and renewing pharmaceutical interest in these two drug classes.

Encapsulation of LXR ligand by D-Nap-GFFY hydrogel enhances anti-tumorigenic actions of LXR and removes LXR-induced lipogenesis

Background and purpose: Activation of liver X receptor (LXR) by its ligand T0901317 (T317) enhances interferon-γ (IFNγ) production to inhibit tumor growth. However, induction of severe hypertriglyceridemia and fatty liver by T317 limits its application. The naphthylacetic acid modified D-enantiomeric-glycine-phenylalanine-phenylalanine-tyrosine (D-Nap-GFFY) can form a nanofiber hydrogel which is selectively taken up by antigen-presenting cells (APCs). In this study, we determined if D-Nap-GFFY-encapsulated T317 (D-Nap-GFFY-T317) can potently inhibit tumor growth while having no adverse lipogenic effects on the liver. Methods: We prepared D-Nap-GFFY-T317 nanofiber hydrogel and subcutaneously injected it into IFNγ deficient (IFNγ^-/-) and wild-type (WT) mice with lung carcinoma, either inoculated LLC1 cells or urethane-induced carcinoma. Mice received oral T317 administration were used for comparison. Effects of treatment on tumor growth, lipogenesis and involved mechanisms were investigated. Results: Compared with T317 oral administration, injection of D-Nap-GFFY-T317 more potently inhibited LLC1 tumor growth in mice. The inhibition was dependent on LXR-activated IFNγ expression in APCs. D-Nap-GFFY-T317 increased M1 while reducing M2 type macrophages in tumors. Associated with activation of IFNγ expression, D-Nap-GFFY-T317 enhanced dendritic cell maturation and infiltration into tumors, increased CD3⁺/CD8⁺ cells in tumors, and inhibited tumor angiogenesis. Similarly, D-Nap-GFFY-T317 more potently inhibited growth of urethane-induced lung carcinomas than T317 oral administration. In these two tumor models, T317 oral administration, but not D-Nap-GFFY-T317 injection, activated hepatic lipogenesis and induced fatty liver. Conclusion: Our study demonstrates that D-Nap-GFFY-T317 inhibits lung tumor growth without adverse effects on the liver, indicating the hydrogel-encapsulated LXR ligand might be a novel therapy for tumor treatment.

Disrupted Lipid Metabolism in Multiple Sclerosis: A Role for Liver X Receptors?

Multiple sclerosis (MS) is a chronic neurological disease driven by autoimmune, inflammatory and neurodegenerative processes leading to neuronal demyelination and subsequent degeneration. Systemic lipid metabolism is disturbed in people with MS, and lipid metabolic pathways are crucial to the protective process of remyelination. The lipid-activated transcription factors liver X receptors (LXRs) are important integrators of lipid metabolism and immunity. Consequently, there is a strong interest in targeting these receptors in a number of metabolic and inflammatory diseases, including MS. We have reviewed the evidence for involvement of LXR-driven lipid metabolism in the dysfunction of peripheral and brain-resident immune cells in MS, focusing on human studies, both the relapsing remitting and progressive phases of the disease are discussed. Finally, we discuss the therapeutic potential of modulating the activity of these receptors with existing pharmacological agents and highlight important areas of future research.

Screening for liver X receptor modulators: Where are we and for what use?

Liver X receptors (LXRs) are members of the nuclear receptor superfamily that are canonically activated by oxidized derivatives of cholesterol. Since the mid-90s, numerous groups have identified LXRs as endocrine receptors that are involved in the regulation of various physiological functions. As a result, when their expression is genetically modified in mice, phenotypic analyses reveal endocrine disorders ranging from infertility to diabetes and obesity, nervous system pathologies such Alzheimer's or Parkinson's disease, immunological disturbances, inflammatory response, and enhancement of tumour development. Based on such findings, it appears that LXRs could constitute good pharmacological targets to prevent and/or to treat these diseases. This review discusses the various aspects of LXR drug discovery, from the tools available for the screening of potential LXR modulators to the current situational analysis of the drugs in development. LINKED ARTICLES: This article is part of a themed issue on Oxysterols, Lifelong Health and Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.16/issuetoc.

Synthetic high-density lipoproteins loaded with an antiplatelet drug for efficient inhibition of thrombosis in mice

Antiplatelet agents offer a desirable approach to thrombosis prevention through the reduction of platelet reactivity. However, major bleeding events greatly attenuate the clinical outcomes of most antithrombotic agents. Therefore, the development of safer and more effective strategies to prevent vascular occlusion and avoid bleeding is urgently needed. A reconstituted nanoparticle, synthetic high-density lipoprotein (sHDL), which mimics the native HDL, has been established as clinically safe and is easily manufactured on a large scale. In this study, we propose that the delivery of the antiplatelet drug ML355, a selective inhibitor of 12(S)-lipoxygenase (12-LOX), by sHDL will efficiently inhibit thrombosis by targeting ML355 to the intended site of action, improving the pharmaceutical profile and harnessing the innate antithrombotic efficacy of the sHDL carrier. Our data show that ML355-sHDL exhibits more potent inhibition of thrombus formation in both small arterioles and larger arteries in mice without impairing the normal hemostasis in vivo.

Nanoparticle-based "Two-pronged" approach to regress atherosclerosis by simultaneous modulation of cholesterol influx and efflux

Reduction of lipoprotein uptake by macrophages and stimulation of cholesterol efflux are two essential steps required for atherosclerotic plaque regression. We used the optimized mannose-functionalized dendrimeric nanoparticle (mDNP)-based platform for macrophage-specific delivery of therapeutics to simultaneously deliver SR-A siRNA (to reduce LDL uptake) and LXR ligand (LXR-L, to stimulate cholesterol efflux) - a novel "Two-pronged" approach to facilitate plaque regression. mDNP-mediated delivery of SR-A siRNA led to a significant reduction in SR-A expression with a corresponding decrease in uptake of oxLDL. Delivery of LXR-L increased expression of ABCA1/G1 and cholesterol efflux. Combined delivery of siRNA and LXR-L led to a significantly greater decrease in macrophage cholesterol content compared to either treatment alone. Administration of this in vitro optimized formulation of mDNP complexed with SR-A-siRNA and LXR-L (Two-pronged complex) to atherosclerotic LDLR-/- mice fed western diet (TD88137) led to significant regression of atherosclerotic plaques with a corresponding decrease in aortic cholesterol content.

Lipoprotein-based drug delivery

Lipoproteins (LPs) are circulating heterogeneous nanoparticles produced by the liver and intestines. LPs play a major role in the transport of dietary and endogenous lipids to target cells through cell membrane receptors or cell surface-bound lipoprotein lipase. The stability, biocompatibility, and selective transport of LPs make them promising delivery vehicles for various therapeutic and imaging agents. This review discusses isolation, manufacturing, and drug loading techniques used for LP-based drug delivery, as well as recent applications for diagnosis and treatment of cancer, atherosclerosis, and other life-threatening diseases.

Advanced nanomedicines for the treatment of inflammatory diseases

Inflammation, a common feature of many diseases, is an essential immune response that enables survival and maintains tissue homeostasis. However, in some conditions, the inflammatory process becomes detrimental, contributing to the pathogenesis of a disease. Targeting inflammation by using nanomedicines (i.e. nanoparticles loaded with a therapeutic active principle), either through the recognition of molecules overexpressed onto the surface of activated macrophages or endothelial cells, or through enhanced vasculature permeability, or even through biomimicry, offers a promising solution for the treatment of inflammatory diseases. After providing a brief insight on the pathophysiology of inflammation and current therapeutic strategies, the review will discuss, at a pre-clinical stage, the main innovative nanomedicine approaches that have been proposed in the past five years for the resolution of inflammatory disorders, finally focusing on those currently in clinical trials.

Pharmacokinetics of T0901317 in mouse serum and tissues using a validated UFLC-IT-TOF/MS method

T0901317, a liver X receptors (LXRs) agonist with high-affinity, is widely used to explore the functions of LXRs in various diseases such as atherosclerosis and Alzheimer's disease. However, there is currently little information available about the pharmacokinetics (PK) behavior of T0901317. Here we established a novel ultrafast liquid chromatography-high resolution mass spectrometry method to quantify the concentration of T0901317 in serum, liver, and brain. The chromatographic separation was attained on a C18 (2.1 × 100 mm, 1.8 μm) column using acetonitrile and 0.1 % of formic acid in water as mobile phase operated in gradient elution mode. The mass detection was carried out using negative ions m/z 479.9809 and 322.0882 for T0901317 and internal standard, respectively. The proposed method was fully validated according to the FDA guidelines, and it generally provides good results in terms of linearity (r² > 0.99), precision (RSD < 18 % and 12 % for LLOQ and other QC levels, respectively), accuracy (between 92.30 % and 108.16 %), and matrix effect (between 86.56 % and 113.81 %). We then for the first time determined and computed the PK parameters of T0901317 in mouse after intraperitoneal administration of a 20 mg/kg dosage. The peak times (T_max) in serum, liver, and brain were 1.5, 1.5, and 4 h, respectively, while the half-lives (t_1/2) were 4.9, 3.3, and 4.5 h, respectively. Taken together, our results provide a significant choice to study the PK property of T0901317, from which the design of the dosing and sampling protocols of LXRs receptor-antagonist experiments employing T0901317 can also benefit.

Functional peptide-based drug delivery systems

Peptides are one of the most important functional motifs for constructing smart drug delivery systems (DDSs). Functional peptides can be conjugated with drugs or carriers via covalent bonds, or assembled into DDSs via supramolecular forces, which enables the DDSs to acquire desired functions such as targeting and/or environmental responsiveness. In this mini review, we first introduce the different types of functional peptides that are commonly used for constructing DDSs, and we highlight representative strategies for designing smart DDSs by using functional peptides in the past few years. We also state the challenges of peptide-based DDSs and come up with prospects.