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Dyslipidemia, characterized by higher serum concentrations of low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), triglyceride (TG), and lower serum concentrations of high-density lipoprotein cholesterol (HDL-C), is confirmed as a hallmark of cardiovascular diseases (CVD), posing serious risks to the future health of humans. Aside from the role of HDL-C concentrations, the capacity of cholesterol efflux to HDL is being identified as an enssential messurement for the dyslipidemic morbidity. Through inducing the progression of reverse cholesterol transport (RCT), the HDL-related cholesterol efflux plays a vital role in atherosclerotic plaque formation. In addition, increasing results demonstrated that the relationships between cholesterol efflux and cardiovascular events might be influenced by multiple factors, such as atherosclerosis, diabetes, and, inflammatory diseases. These risk factors could affect the intracellular composition of HDL, which might subsqently influence the cholesterol efflux process induced by HDL particle. In the present comprehensive article, we summarize the latest findings which described the modulatory roles of HDL in cardiometabolic disorders and inflammatory related diseases, focusing on its capacity in mediating cholesterol efflux. Moreover, the potential mechanisms whereby HDL regulate the risk of cardiometabolic disorders or inflammatory related diseases, at least partly, via cholesterol efflux pathway, are also well-listed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Decades of research have reshaped our understanding of high-density lipoprotein (HDL) , shifting our focus from cholesterol (C) levels to multifaceted functionalities. Epidemiological studies initially suggested an association between HDL-C levels and cardiovascular disease (CVD) risk; however, such a simple association has not been indicated by recent studies. Notably, genome-wide studies have highlighted discrepancies between HDL-C levels and CVD outcomes, urging a deeper exploration of the role of HDL. The key to this shift lies in elucidating the role of HDL in reverse cholesterol transport (RCT), which is a fundamental anti-atherosclerotic mechanism. Understanding RCT has led to the identification of therapeutic targets and novel interventions for atherosclerosis. However, clinical trials have underscored the limitations of HDL-C as a therapeutic target, prompting the re-evaluation of the role of HDL in disease prevention. Further investigations have revealed the involvement of HDL composition in various diseases other than CVD, including chronic kidney disease, Alzheimer's disease, and autoimmune diseases. The anti-inflammatory, antioxidative, and anti-infectious properties of HDL have emerged as crucial aspects of its protective function, opening new avenues for novel biomarkers and therapeutic targets. Omics technologies have provided insights into the diverse composition of HDL, revealing disease-specific alterations in the HDL proteome and lipidome. In addition, combining cell-based and cell-free assays has facilitated the evaluation of the HDL functionality across diverse populations, offering the potential for personalized medicine. Overall, a comprehensive understanding of HDL multifunctionality leads to promising prospects for future clinical applications and therapeutic developments, extending beyond cardiovascular health.

The association between high-density lipoprotein (HDL) cholesterol and breast cancer (BC) remains controversial due to the high complexity of the HDL particle and its functionality. The HDL proteome was determined in newly diagnosed BC classified according to the molecular type [luminal A or B (LA or LB), HER2, and triple-negative (TN)] and clinical stage of the disease. Women (n = 141) aged between 18 and 80 years with BC, treatment-naïve, and healthy women [n = 103; control group (CT)], matched by age and body mass index, were included. Data-independent acquisition (DIA) proteomics was performed in isolated HDL (D = 1.063-1.21 g/mL). Results: Paraoxonase1, carnosine dipeptidase1, immunoglobulin mMu heavy chain constant region (IGHM), apoA-4, and transthyretin were reduced, and serum amyloid A2 and tetranectin were higher in BC compared to CT. In TNBC, apoA-1, apoA-2, apoC-2, and apoC-4 were reduced compared to LA, LB, and HER2, and apoA-4 compared to LA and HER2. ComplementC3, lambda immunoglobulin2/3, serpin3, IGHM, complement9, alpha2 lysine rich-glycoprotein1, and complement4B were higher in TNBC in comparison to all other types; complement factor B and vitamin D-binding protein were in contrast to LA and HER2, and plasminogen compared to LA and LB. In grouped stages III + IV, tetranectin and alpha2-macroglobulin were reduced, and haptoglobin-related protein; lecithin cholesterol acyltransferase, serum amyloid A1, and IGHM were increased compared to stages I + II. Conclusions: A differential proteomic profile of HDL in BC based on tumor molecular classification and the clinical stage of the disease may contribute to a better understanding of the association of HDL with BC pathophysiology, treatment, and outcomes.

High-density lipoproteins (HDL) are micelle-like particles consisting of a core of triglycerides and cholesteryl esters surrounded by a shell of phospholipid, cholesterol, and apolipoproteins. HDL is considered "good" cholesterol, and its concentration in plasma is used clinically in assessing cardiovascular health. However, these particles vary in structure, composition, and therefore function, and thus can be resolved into subpopulations, some of which have specific cardioprotective properties. Mass measurements of HDL by charge detection mass spectrometry (CD-MS) previously revealed seven distinct subpopulations which could be delineated by mass and charge [Lutomski, C. A. et al. Anal. Chem. 2018]. Here, we investigate the thermal stabilities of these subpopulations; upon heating, the particles within each subpopulation undergo structural rearrangements with distinct transition temperatures. In addition, we find evidence for many new families of structures within each subpopulation; at least 15 subspecies of HDL are resolved. These subspecies vary in size, charge, and thermal stability. While this suggests that these new subspecies have unique molecular compositions, we cannot rule out the possibility that we have found evidence for new structural forms within the known subpopulations. The ability to resolve new subspecies of HDL particles may be important in understanding and delineating the role of unique particles in cardiovascular health and disease.

Macrophages in atherosclerotic lesions exhibit a spectrum of behaviours or phenotypes. The phenotypic distribution of monocyte-derived macrophages (MDMs), its correlation with MDM lipid content, and relation to blood lipoprotein densities are not well understood. Of particular interest is the balance between low density lipoproteins (LDL) and high density lipoproteins (HDL), which carry bad and good cholesterol respectively. To address these issues, we have developed a mathematical model for early atherosclerosis in which the MDM population is structured by phenotype and lipid content. The model admits a simpler, closed subsystem whose analysis shows how lesion composition becomes more pathological as the blood density of LDL increases relative to the HDL capacity. We use asymptotic analysis to derive a power-law relationship between MDM phenotype and lipid content at steady-state. This relationship enables us to understand why, for example, lipid-laden MDMs have a more inflammatory phenotype than lipid-poor MDMs when blood LDL lipid density greatly exceeds HDL capacity. We show further that the MDM phenotype distribution always attains a local maximum, while the lipid content distribution may be unimodal, adopt a quasi-uniform profile or decrease monotonically. Pathological lesions exhibit a local maximum in both the phenotype and lipid content MDM distributions, with the maximum at an inflammatory phenotype and near the lipid content capacity respectively. These results illustrate how macrophage heterogeneity arises in early atherosclerosis and provide a framework for future model validation through comparison with single-cell RNA sequencing data., (© 2024. The Author(s).)

Low levels of high-density lipoprotein (HDL) and impaired HDL functionality have been consistently associated with increased susceptibility to infection and its serious consequences. This has been attributed to the critical role of HDL in maintaining cellular lipid homeostasis, which is essential for the proper functioning of immune and structural cells. HDL, a multifunctional particle, exerts pleiotropic effects in host defense against pathogens. It functions as a natural nanoparticle, capable of sequestering and neutralizing potentially harmful substances like bacterial lipopolysaccharides. HDL possesses antiviral activity, preventing viruses from entering or fusing with host cells, thereby halting their replication cycle. Understanding the complex relationship between HDL and the immune system may reveal innovative targets for developing new treatments to combat infectious diseases and improve patient outcomes. This review aims to emphasize the role of HDL in influencing the course of bacterial and viral infections and its and its therapeutic potential., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Monocytes are innate immune cells that are continuously produced in bone marrow which enter and circulate the vasculature. In response to nutrient scarcity, monocytes migrate back to bone marrow, where, upon refeeding, they are rereleased back into the bloodstream to replenish the circulation. In humans, the variability in monocyte behavior in response to fasting and refeeding has not been characterized. To investigate monocyte dynamics in humans, we measured blood monocyte fluctuations in 354 clinically healthy individuals after a 12-h overnight fast and at 3 and 6 h after consuming a mixed macronutrient challenge meal. Using cluster analysis, we identified three distinct monocyte behaviors. Group 1 was characterized by relatively low fasting monocyte counts that markedly increased after consuming the test meal. Group 2 was characterized by relatively high fasting monocyte counts that decreased after meal consumption. Group 3 , like Group 1 , was characterized by lower fasting monocyte counts but increased to a lesser extent after consuming the meal. Although monocyte fluctuations observed in Groups 1 and 3 align with the current paradigm of monocyte dynamics in response to fasting and refeeding, the atypical dynamic observed in Group 2 does not. Although generally younger in age, Group 2 subjects had lower whole body carbohydrate oxidation rates, lower HDL-cholesterol levels, delayed postprandial declines in salivary cortisol, and reduced postprandial peripheral microvascular endothelial function. These unique characteristics were not explained by group differences in age, sex, or body mass index (BMI). Taken together, these results highlight distinct patterns of monocyte responsiveness to natural fluctuations in dietary fuel availability. NEW & NOTEWORTHY Our study composed of adult volunteers revealed that monocyte dynamics exhibit a high degree of individual variation in response to fasting and refeeding. Although circulating monocytes in most volunteers behaved in ways that align with previous reports, many exhibited atypical dynamics demonstrated by elevated fasting blood monocyte counts that sharply decreased after meal consumption. This group was also distinguished by lower HDL levels, reduced postprandial endothelial function, and a delayed postprandial decline in salivary cortisol.

The association between high-density lipoprotein cholesterol (HDL-C) and cardiovascular disease (CVD) is controversial. HDL-C is one content type of high-density lipoprotein (HDL). HDL consists of diverse proteins and lipids and can be classified into different subclasses based on size, shape, charge, and density, and can change dynamically in disease states. Therefore, HDL-C levels alone cannot represent HDLs' cardioprotective role. In this review, we summarized the methods for separating HDL subclasses, the studies on the association between HDL subclasses and cardiovascular risk (CVR), and the impact of lipid-modifying medications and nonpharmacological approaches (exercise training, dietary omega fatty acids, and low-density lipoprotein apheresis) on HDL subclasses. As HDL is a natural nanoplatform, recombinant HDLs (rHDLs) have been used as a delivery system in vivo by loading small interfering RNA, drugs, contrast agents, etc. Therefore, we further reviewed the HDL subclasses used in rHDLs and their advantages and disadvantages. This review would provide recommendations and guidance for future studies on HDL subclasses' cardioprotective roles.

Apolipoprotein A-I(ApoA-I) is a member of blood apolipoproteins, it is the main component of High density lipoprotein(HDL). ApoA-I undergoes a series of complex processes from its generation to its composition as spherical HDL. It not only has a cholesterol reversal transport function, but also has a function in modulating the inflammatory response. ApoA-I exerts its anti-inflammatory effects mainly by regulating the functions of immune cells, such as monocytes/macrophages, dendritic cells, neutrophils, and T lymphocytes. It also modulates the function of vascular endothelial cells and adipocytes. Additionally, ApoA-I directly exerts anti-inflammatory effects against pathogenic microorganisms or their products. Intensive research on ApoA-I will hopefully lead to better diagnosis and treatment of inflammatory diseases., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Tao, Tao, Wang and Wu.)

Cytotoxic activity has been reported for the xanthone α-mangostin (AMN) against Glioblastoma multiforme (GBM), an aggressive malignant brain cancer with a poor prognosis. Recognizing that AMN's high degree of hydrophobicity is likely to limit its systemic administration, we formulated AMN using reconstituted high-density lipoprotein (rHDL) nanoparticles. The photophysical characteristics of the formulation, including fluorescence lifetime and steady-state anisotropy, indicated that AMN was successfully incorporated into the rHDL nanoparticles. To our knowledge, this is the first report on the fluorescent characteristics of AMN with an HDL-based drug carrier. Cytotoxicity studies in a 2D culture and 3D spheroid model of LN-229 GBM cells and normal human astrocytes showed an enhanced therapeutic index with the rHDL-AMN formulation compared to the unincorporated AMN and Temozolomide, a standard GBM chemotherapy agent. Furthermore, treatment with the rHDL-AMN facilitated a dose-dependent upregulation of autophagy and reactive oxygen species generation to a greater extent in LN-229 cells compared to astrocytes, indicating the reduced off-target toxicity of this novel formulation. These studies indicate the potential therapeutic benefits to GBM patients via selective targeting using the rHDL-AMN formulation.

Background: Individuals with type 1 diabetes (T1D) generally have normal or even higher HDL (high-density lipoprotein)-cholesterol levels than people without diabetes yet are at increased risk for atherosclerotic cardiovascular disease (CVD). Human HDL is a complex mixture of particles that can vary in cholesterol content by >2-fold. To investigate if specific HDL subspecies contribute to the increased atherosclerosis associated with T1D, we created mouse models of T1D that exhibit human-like HDL subspecies. We also measured HDL subspecies and their association with incident CVD in a cohort of people with T1D., Methods: We generated LDL receptor-deficient ( Ldlr -/- ) mouse models of T1D expressing human APOA1 (apolipoprotein A1). Ldlr -/- APOA1 Tg mice exhibited the main human HDL subspecies. We also generated Ldlr -/- APOA1 Tg T1D mice expressing CETP (cholesteryl ester transfer protein), which had lower concentrations of large HDL subspecies versus mice not expressing CETP. HDL particle concentrations and sizes and proteins involved in lipoprotein metabolism were measured by calibrated differential ion mobility analysis and targeted mass spectrometry in the mouse models of T1D and in a cohort of individuals with T1D. Endothelial transcytosis was analyzed by total internal reflection fluorescence microscopy., Results: Diabetic Ldlr -/- APOA1 Tg mice were severely hyperglycemic and hyperlipidemic and had markedly elevated plasma APOB levels versus nondiabetic littermates but were protected from the proatherogenic effects of diabetes. Diabetic Ldlr -/- APOA1 Tg mice expressing CETP lost the atheroprotective effect and had increased lesion necrotic core areas and APOB accumulation, despite having lower plasma APOB levels. The detrimental effects of low concentrations of larger HDL particles in diabetic mice expressing CETP were not explained by reduced cholesterol efflux. Instead, large HDL was more effective than small HDL in preventing endothelial transcytosis of LDL mediated by scavenger receptor class B type 1. Finally, in humans with T1D, increased concentrations of larger HDL particles relative to APOB100 negatively predicted incident CVD independently of HDL-cholesterol levels., Conclusions: Our results suggest that the balance between APOB lipoproteins and the larger HDL subspecies contributes to atherosclerosis progression and incident CVD in the setting of T1D and that larger HDLs exert atheroprotective effects on endothelial cells rather than by promoting macrophage cholesterol efflux., Competing Interests: K.E. Bornfeldt serves on the Scientific Advisory Board of Esperion Therapeutics. The other authors report no conflicts.

Low levels of high-density lipoprotein-cholesterol (HDL-C) is considered a major cardiovascular risk factor. However, recent studies have suggested a more U-shaped association between HDL-C and cardiovascular disease. It has been shown that the cardioprotective effect of HDL is related to the functions of HDL particles rather than their cholesterol content. HDL particles are highly heterogeneous and have multiple functions relevant to cardiometabolic conditions including cholesterol efflux capacity, anti-oxidative, anti-inflammatory, and vasoactive properties. There are quantitative and qualitative changes in HDL as well as functional abnormalities in both type 1 and type 2 diabetes. Non-enzymatic glycation, carbamylation, oxidative stress, and systemic inflammation can modify the HDL composition and therefore the functions, especially in situations of poor glycemic control. Studies of HDL proteomics and lipidomics have provided further insights into the structure-function relationship of HDL in diabetes. Interestingly, HDL also has a pleiotropic anti-diabetic effect, improving glycemic control through improvement in insulin sensitivity and β-cell function. Given the important role of HDL in cardiometabolic health, HDL-based therapeutics are being developed to enhance HDL functions rather than to increase HDL-C levels. Among these, recombinant HDL and small synthetic apolipoprotein A-I mimetic peptides may hold promise for preventing and treating diabetes and cardiovascular disease., (© 2024 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.)

Atherosclerosis is a chronic disease of the arteries characterised by the accumulation of lipids and lipid-engorged cells in the artery wall. Early plaque growth is aggravated by the deposition of low density lipoproteins (LDL) in the wall and the subsequent immune response. High density lipoproteins (HDL) counterbalance the effects of LDL by accepting cholesterol from macrophages and removing it from the plaque. In this paper, we develop a free boundary multiphase model to investigate the effects of LDL and HDL on early plaque development. We examine how the rates of LDL and HDL deposition affect cholesterol accumulation in macrophages, and how this impacts cell death rates and emigration. We identify a region of LDL-HDL parameter space where plaque growth stabilises for low LDL and high HDL influxes, due to macrophage emigration and HDL clearance that counterbalances the influx of new cells and cholesterol. We explore how the efferocytic uptake of dead cells and the recruitment of new macrophages affect plaque development for a range of LDL and HDL influxes. Finally, we consider how changes in the LDL-HDL profile can change the course of plaque development. We show that changes towards lower LDL and higher HDL can slow plaque growth and even induce regression. We find that these changes have less effect on larger, more established plaques, and that temporary changes will only slow plaque growth in the short term., Competing Interests: Declaration of competing interest All authors declare that they have no conflicts of interest to disclose., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Tumor heterogeneity remains a significant obstacle in cancer therapy due to diverse cells with varying treatment responses. Cancer stem-like cells (CSCs) contribute significantly to intratumor heterogeneity, characterized by high tumorigenicity and chemoresistance. CSCs reside in the depth of the tumor, possessing low reactive oxygen species (ROS) levels and robust antioxidant defense systems to maintain self-renewal and stemness. A nanotherapeutic strategy is developed using tumor-penetrating peptide iRGD-modified high-density lipoprotein (HDL)-mimetic nanodiscs (IPCND) that ingeniously loaded with pyropheophorbide-a (Ppa), bis (2-hydroxyethyl) disulfide (S-S), and camptothecin (CPT) by synthesizing two amphiphilic drug-conjugated sphingomyelin derivatives. Photoactivatable Ppa can generate massive ROS which as intracellular signaling molecules effectively shut down self-renewal and trigger differentiation of the CSCs, while S-S is utilized to deplete GSH and sustainably imbalance redox homeostasis by reducing ROS clearance. Simultaneously, the depletion of GSH is accompanied by the release of CPT, which leads to subsequent cell death. This dual strategy successfully disturbed the redox equilibrium of CSCs, prompting their differentiation and boosting the ability of CPT to kill CSCs upon laser irradiation. Additionally, it demonstrated a synergistic anti-cancer effect by concurrently eliminating therapeutically resistant CSCs and bulk tumor cells, effectively suppressing tumor growth in CSC-enriched heterogeneous colon tumor mouse models., (© 2024 Wiley‐VCH GmbH.)

Atherosclerotic cardiovascular disease (ASCVD) represents the primary cause of mortality among patients with Type 2 Diabetes Mellitus (T2DM). In this population, High-Density Lipoprotein (HDL) particles exhibit abnormalities in number, composition, and function, culminating in diminished anti-atherosclerotic capabilities despite normal HDL cholesterol (HDL-C) concentrations. Hyperglycemic conditions contribute to these alterations in HDL kinetics, composition, and function, causing T2DM patients' HDL particles to exhibit decreased concentrations of diverse lipid species and proteins. Treatment of hyperglycemia has the potential to correct abnormal HDL particle attributes in T2DM; however, pharmacological interventions, including metformin and thiazolidinediones, yield inconsistent outcomes with respect to HDL-C concentrations and functionality. Despite numerous attempts with diverse drugs, pharmacologically augmenting HDL-C levels has not resulted in clinical benefits in mitigating ASCVD risk. In contrast, reducing Low Density Lipoprotein cholesterol (LDL-C) via statins and ezetimibe has demonstrated significant efficacy in curtailing CVD risk among T2DM individuals. Promising results have been observed in animal models and early-phase trials utilizing recombinant HDL and Lecitin Cholesterol Acyl Transferase (LCAT) -enhancing agents, but the evaluation of their efficacy and safety in large-scale clinical trials is ongoing. While aberrant HDL metabolism constitutes a prevalent aspect of dyslipidemia in T2DM, HDL cholesterol concentrations and composition no longer offer valuable insights for informing therapeutic decisions. Nevertheless, HDL metabolism remains a critical research area in T2DM, necessitating further investigation to elucidate the role of HDL particles in the development of diabetes-associated complications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2023 Elsevier B.V. All rights reserved.)

Apolipoprotein A-I (apoA-I), the primary protein component of plasma high-density lipoproteins (HDL), is comprised of two structural regions, an N-terminal amphipathic α-helix bundle domain (residues 1-184) and a hydrophobic C-terminal domain (residues 185-243). When a recombinant fusion protein construct [bacterial pelB leader sequence - human apoA-I (1-243)] was expressed in Escherichia coli shaker flask cultures, apoA-I was recovered in the cell lysate. By contrast, when the C-terminal domain was deleted from the construct, large amounts of the truncated protein, apoA-I (1-184), were recovered in the culture medium. Consequently, following pelB leader sequence cleavage in the E. coli periplasmic space, apoA-I (1-184) was secreted from the bacteria. When the pelB-apoA-I (1-184) fusion construct was expressed in a 5 L bioreactor, substantial foam production (~30 L) occurred. Upon foam collection and collapse into a liquid foamate, SDS-PAGE revealed that apoA-I (1-184) was the sole major protein present. Incubation of apoA-I (1-184) with phospholipid vesicles yielded reconstituted HDL (rHDL) particles that were similar in size and cholesterol efflux capacity to those generated with full-length apoA-I. Mass spectrometry analysis confirmed that pelB leader sequence cleavage occurred and that foam fractionation did not result in unwanted protein modifications. The facile nature and scalability of bioreactor-based apolipoprotein foam fractionation provide a novel means to generate a versatile rHDL scaffold protein., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

High-density lipoprotein (HDL) is a group of small, dense, and protein-rich lipoproteins that play a role in cholesterol metabolism and various cellular processes. Decreased levels of HDL and HDL dysfunction are commonly observed in individuals with type 2 diabetes mellitus (T2DM), which is also associated with an increased risk for cardiovascular disease (CVD). Due to hyperglycemia, oxidative stress, and inflammation that develop in T2DM, HDL undergoes several post-translational modifications such as glycation, oxidation, and carbamylation, as well as other alterations in its lipid and protein composition. It is increasingly recognized that the generation of HDL modifications in T2DM seems to be the main cause of HDL dysfunction and may in turn influence the development and progression of T2DM and its related cardiovascular complications. This review provides a general introduction to HDL structure and function and summarizes the main modifications of HDL that occur in T2DM. Furthermore, the potential impact of HDL modifications on the pathogenesis of T2DM and CVD, based on the altered interactions between modified HDL and various cell types that are involved in glucose homeostasis and atherosclerotic plaque generation, will be discussed. In addition, some perspectives for future research regarding the T2DM-related HDL modifications are addressed.

Lipid nanoparticles often contain a phosphatidylcholine with a long chain fatty acid, 1,2-distearoyl- sn-glycero -3-phosphocholine (DSPC). However, their preparation often encounters difficulties such as the inability to yield <20 nm nanoparticles due to the aggregation-prone behavior of DSPC. High-density lipoproteins (HDLs) are ∼10 nm protein-bound lipid nanoparticles in our body, and microfluidic preparations of HDL-mimicking nanoparticles (μHDL) have been reported. Herein, we report a new microfluidic mixing mode that enables preparation of μHDL with DSPC in high yield (≥90% on a protein basis). The critical mechanism of this mode is a spontaneous asymmetric distribution of the ethanol flow injected in a symmetric manner followed by turbulent mixing in a simple rectangular parallelepiped-shaped chip.

Immunotoxicity remains a major hindrance to chemotherapy in cancer therapy. Nanocarriers may alleviate the immunotoxicity, but the optimal design remains unclear. Here, we created two variants of maytansine (DM1)-loaded synthetic high-density lipoproteins (D-sHDL) with either physically entrapped ( E D-sHDL) or chemically conjugated ( C D-sHDL) DM1. We found that C D-sHDL showed less accumulation in the tumor draining lymph nodes (DLNs) and femur, resulting in a lower toxicity against myeloid cells than E D-sHDL via avoiding scavenger receptor class B type 1 (SR-B1)-mediated DM1 transportation into the granulocyte-monocyte progenitors and dendritic cells. Therefore, higher densities of lymphocytes in the tumors, DLNs, and blood were recorded in mice receiving C D-sHDL, leading to a better efficacy and immune memory of C D-sHDL against colon cancer. Furthermore, liposomes with conjugated DM1 ( C D-Lipo) showed lower immunotoxicity than those with entrapped drug ( E D-Lipo) through the same mechanism after apolipoprotein opsonization. Our findings highlight the critical role of drug loading patterns in dictating the biological fate and activity of nanomedicine.

Several studies in animal models and human cohorts have recently suggested that HDLs (high-density lipoproteins) not only modulate innate immune responses but also adaptative immune responses, particularly CD4+ T cells. CD4+ T cells are central effectors and regulators of the adaptive immune system, and any alterations in their homeostasis contribute to the pathogenesis of cardiovascular diseases, autoimmunity, and inflammatory diseases. In this review, we focus on how HDLs and their components affect CD4+ T-cell homeostasis by modulating cholesterol efflux, immune synapsis, proliferation, differentiation, oxidative stress, and apoptosis. While the effects of apoB-containing lipoproteins on T cells have been relatively well established, this review focuses specifically on new connections between HDL and CD4+ T cells. We present a model where HDL may modulate T cells through both direct and indirect mechanisms., Competing Interests: Disclosures None.

Cardiovascular disease (CVD) has been the leading cause of death worldwide. As a chronic inflammatory disease, atherosclerosis (AS) acts as the initiating factor for CVD and reactive oxygen species (ROS) play a vital role in its development. Superoxide dismutases (SOD) can alleviate the detrimental effects of ROS and serve as the first line of defense through detoxifying the products derived from oxidative stress in vivo. Considering the potential preventive effects of high-density lipoprotein (HDL) on AS and the close relationship between CuZn superoxide dismutase (CuZnSOD) and HDL, the present work investigated whether CuZnSOD overexpression in swine could improve the function of HDL. Seven CuZnSOD transgenic swine, constructed by sperm and magnetic nanoparticles, demonstrated overexpressed CuZnSOD in the liver (P < 0.01) but comparable level to control in plasma (P > 0.05). CuZnSOD overexpression significantly down-regulated the levels of triglyceride (TG), apolipoprotein A-I (apoA-I) (P < 0.05), and high-density lipoprotein cholesterol (HDL-C) (P < 0.01) in plasma. In the presence of CuZnSOD overexpression, HDL3 significantly inhibited levels of IL-6 and TNF-α induced by oxidized low-density lipoprotein (oxLDL) (P < 0.05), indicating enhanced anti-inflammatory activity of HDL. At the same time, HDL-mediated cholesterol efflux did not decrease (P > 0.05). CuZnSOD overexpression improves the anti-inflammatory function of HDL despite decreased levels of HDL-C. In Conclusion, CuZnSOD overexpression improves HDL function in swine., Competing Interests: Declaration of Competing Interest All authors declare that they have no conflicts of interest to this work., (Copyright © 2024. Published by Elsevier Inc.)

Atherosclerosis is the build-up of fatty plaques within blood vessel walls, which can occlude the vessels and cause strokes or heart attacks. It gives rise to both structural and biomolecular changes in the vessel walls. Current single-modality imaging techniques each measure one of these two aspects but fail to provide insight into the combined changes. To address this, our team has developed a dual-modality imaging system which combines optical coherence tomography (OCT) and fluorescence imaging that is optimized for a porphyrin lipid nanoparticle that emits fluorescence and targets atherosclerotic plaques. Atherosclerosis-prone apolipoprotein (Apo)e -/- mice were fed a high cholesterol diet to promote plaque development in descending thoracic aortas. Following infusion of porphyrin lipid nanoparticles in atherosclerotic mice, the fiber-optic probe was inserted into the aorta for imaging, and we were able to robustly detect a porphyrin lipid-specific fluorescence signal that was not present in saline-infused control mice. We observed that the nanoparticle fluorescence colocalized in areas of CD68 + macrophages. These results demonstrate that our system can detect the fluorescence from nanoparticles, providing complementary biological information to the structural information obtained from simultaneously acquired OCT., (© 2024. The Author(s).)

As an escalating public health issue, obesity and overweight conditions are predispositions to various diseases and are exacerbated by concurrent chronic inflammation. Nonetheless, extant antiobesity pharmaceuticals (quercetin, capsaicin, catecholamine, etc.) manifest constrained efficacy alongside systemic toxic effects. Effective therapeutic approaches that selectively target adipose tissue, thereby enhancing local energy expenditure, surmounting the limitations of prevailing antiobesity modalities are highly expected. In this context, we developed a temperature-sensitive hydrogel loaded with recombinant high-density lipoprotein (rHDL) to achieve targeted delivery of resveratrol, an adipose browning activator, to adipose tissue. rHDL exhibits self-regulation on fat cell metabolism and demonstrates natural targeting toward scavenger receptor class B type I (SR-BI), which is highly expressed by fat cells, thereby achieving a synergistic effect for the treatment of obesity. Additionally, the dispersion of rHDL@Res in temperature-sensitive hydrogels, coupled with the regulation of their degradation and drug release rate, facilitated sustainable drug release at local adipose tissues over an extended period. Following 24 days' treatment regimen, obese mice exhibited improved metabolic status, resulting in a reduction of 68.2% of their inguinal white adipose tissue (ingWAT). Specifically, rHDL@Res/gel facilitated the conversion of fatty acids to phospholipids (PA, PC), expediting fat mobilization, mitigating triglyceride accumulation, and therefore facilitating adipose tissue reduction. Furthermore, rHDL@Res/gel demonstrated efficacy in attenuating obesity-induced inflammation and fostering angiogenesis in ingWAT. Collectively, this engineered local fat reduction platform demonstrated heightened effectiveness and safety through simultaneously targeting adipocytes, promoting WAT browning, regulating lipid metabolism, and controlling inflammation, showing promise for adipose-targeted therapy.

Severe dengue infections are characterized by endothelial dysfunction shown to be associated with the secreted nonstructural protein 1 (sNS1), making it an attractive vaccine antigen and biotherapeutic target. To uncover the biologically relevant structure of sNS1, we obtained infection-derived sNS1 (isNS1) from dengue virus (DENV)-infected Vero cells through immunoaffinity purification instead of recombinant sNS1 (rsNS1) overexpressed in insect or mammalian cell lines. We found that isNS1 appeared as an approximately 250 kDa complex of NS1 and ApoA1 and further determined the cryoEM structures of isNS1 and its complex with a monoclonal antibody/Fab. Indeed, we found that the major species of isNS1 is a complex of the NS1 dimer partially embedded in a high-density lipoprotein (HDL) particle. Crosslinking mass spectrometry studies confirmed that the isNS1 interacts with the major HDL component ApoA1 through interactions that map to the NS1 wing and hydrophobic domains. Furthermore, our studies demonstrated that the sNS1 in sera from DENV-infected mice and a human patient form a similar complex as isNS1. Our results report the molecular architecture of a biological form of sNS1, which may have implications for the molecular pathogenesis of dengue., Competing Interests: BC, AN, WP, KC, ZS, NT, SL, MW, SW, MC, JL, EO, CR, RS, SV, DL No competing interests declared, (© 2023, Chew, Ngoh, Phoo et al.)

CIGB-258, a 3 kDa peptide from heat shock protein 60, exhibits synergistic anti-inflammatory activity with apolipoprotein A-I (apoA-I) in reconstituted high-density lipoproteins (rHDLs) via stabilization of the rHDL structure. This study explored the interactions between CIGB-258 and apoA-I in the lipid-free state to assess their synergistic effects in the structural and functional enhancement of apoA-I and HDL. A co-treatment of lipid-free apoA-I and CIGB-258 inhibited the cupric ion-mediated oxidation of low-density lipoprotein (LDL) and a lowering of oxidized species in the dose-responsive manner of CIGB-258. The co-presence of CIGB-258 caused a blue shift in the wavelength of maximum fluorescence (WMF) of apoA-I with protection from proteolytic degradation. The addition of apoA-I:CIGB-258, with a molar ratio of 1:0.1, 1:0.5, and 1:1, to HDL 2 and HDL 3 remarkably enhanced the antioxidant ability against LDL oxidation up to two-fold higher than HDL alone. HDL-associated paraoxonase activities were elevated up to 28% by the co-addition of apoA-I and CIGB-258, which is linked to the suppression of Cu 2+ -mediated HDL oxidation with the slowest electromobility. Isothermal denaturation by a urea treatment showed that the co-presence of CIGB-258 attenuated the exposure of intrinsic tryptophan (Trp) and increased the mid-points of denaturation from 2.33 M for apoA-I alone to 2.57 M for an apoA-I:CIGB-258 mixture with a molar ratio of 1:0.5. The addition of CIGB-258 to apoA-I protected the carboxymethyllysine (CML)-facilitated glycation of apoA-I with the prevention of Trp exposure. A co-treatment of apoA-I and CIGB-258 synergistically safeguarded zebrafish embryos from acute death by CML-toxicity, suppressing oxidative stress and apoptosis. In adult zebrafish, the co-treatment of apoA-I+CIGB-258 exerted the highest anti-inflammatory activity with a higher recovery of swimming ability and survivability than apoA-I alone or CIGB-258 alone. A co-injection of apoA-I and CIGB-258 led to the lowest infiltration of neutrophils and interleukin (IL)-6 generation in hepatic tissue, with the lowest serum triglyceride, aspartate transaminase, and alanine transaminase levels in plasma. In conclusion, the co-presence of CIGB-258 ameliorated the beneficial functionalities of apoA-I, such as antioxidant and anti-glycation activities, by enhancing the structural stabilization and protection of apoA-I. The combination of apoA-I and CIGB-258 synergistically enforced the anti-inflammatory effect against CML toxicity in embryos and adult zebrafish.

The prevalence of cardiovascular diseases continues to be a challenge for global health, necessitating innovative solutions. The potential of high-density lipoprotein (HDL) mimetic nanotherapeutics in the context of cardiovascular disease and the intricate mechanisms underlying the interactions between monocyte-derived cells and HDL mimetic showing their impact on inflammation, cellular lipid metabolism, and the progression of atherosclerotic plaque. Preclinical studies have demonstrated that HDL mimetic nanotherapeutics can regulate monocyte recruitment and macrophage polarization towards an anti-inflammatory phenotype, suggesting their potential to impede the progression of atherosclerosis. The challenges and opportunities associated with the clinical application of HDL mimetic nanotherapeutics, emphasize the need for additional research to gain a better understanding of the precise molecular pathways and long-term effects of these nanotherapeutics on monocytes and macrophages to maximize their therapeutic efficacy. Furthermore, the use of nanotechnology in the treatment of cardiovascular diseases highlights the potential of nanoparticles for targeted treatments. Moreover, the concept of theranostics combines therapy and diagnosis to create a selective platform for the conversion of traditional therapeutic medications into specialized and customized treatments. The multifaceted contributions of HDL to cardiovascular and metabolic health via highlight its potential to improve plaque stability and avert atherosclerosis-related problems. There is a need for further research to maximize the therapeutic efficacy of HDL mimetic nanotherapeutics and to develop targeted treatment approaches to prevent atherosclerosis. This review provides a comprehensive overview of the potential of nanotherapeutics in the treatment of cardiovascular diseases, emphasizing the need for innovative solutions to address the challenges posed by cardiovascular diseases., (© 2024. The Author(s).)

The physicochemical characteristics of the various subpopulations of high-density lipoproteins (HDLs) and, in particular, their surface properties determine their ability to scavenge lipids and interact with specific receptors and peptides. Five representative spheroidal HDL subpopulation models were mapped from a previously reported equilibrated coarse-grained (CG) description to an atomistic representation for subsequent molecular dynamics simulation. For each HDL model a range of finer-level analyses was undertaken, including the component-wise characterization of HDL surfaces, the average size and composition of hydrophobic surface patches, dynamic protein secondary structure monitoring, and the proclivity for solvent exposure of the proposed β-amyloid (Aβ) binding region of apolipoprotein A-I (apoA-I), "LN." This study reveals that previously characterized ellipsoidal HDL 3a and HDL 2a models revert to a more spherical geometry in an atomistic representation due to the enhanced conformational flexibility afforded to the apoA-I protein secondary structure, allowing for enhanced surface lipid packing and lower overall surface hydrophobicity. Indeed, the proportional surface hydrophobicity and apoA-I exposure reduced with increasing HDL size, consistent with previous characterizations. Furthermore, solvent exposure of the "LN" region of apoA-I was exclusively limited to the smallest HDL 3c model within the timescale of the simulations, and typically corresponded to a distinct loss in secondary structure across the "LN" region to form part of a significant contiguous hydrophobic patch on the HDL surface. Taken together, these findings provide preliminary evidence for a subpopulation-specific interaction between HDL 3c particles and circulating hydrophobic species such as Aβ via the exposed "LN" region of apoA-I., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Biophysical Society. Published by Elsevier Inc. All rights reserved.)

Background: Cardiovascular events frequently recur after acute myocardial infarction, and low cholesterol efflux - a process mediated by apolipoprotein A1, which is the main protein in high-density lipoprotein - has been associated with an increased risk of cardiovascular events. CSL112 is human apolipoprotein A1 derived from plasma that increases cholesterol efflux capacity. Whether infusions of CSL112 can reduce the risk of recurrent cardiovascular events after acute myocardial infarction is unclear., Methods: We conducted an international, double-blind, placebo-controlled trial involving patients with acute myocardial infarction, multivessel coronary artery disease, and additional cardiovascular risk factors. Patients were randomly assigned to receive either four weekly infusions of 6 g of CSL112 or matching placebo, with the first infusion administered within 5 days after the first medical contact for the acute myocardial infarction. The primary end point was a composite of myocardial infarction, stroke, or death from cardiovascular causes from randomization through 90 days of follow-up., Results: A total of 18,219 patients were included in the trial (9112 in the CSL112 group and 9107 in the placebo group). There was no significant difference between the groups in the risk of a primary end-point event at 90 days of follow-up (439 patients [4.8%] in the CSL112 group vs. 472 patients [5.2%] in the placebo group; hazard ratio, 0.93; 95% confidence interval [CI], 0.81 to 1.05; P = 0.24), at 180 days of follow-up (622 patients [6.9%] vs. 683 patients [7.6%]; hazard ratio, 0.91; 95% CI, 0.81 to 1.01), or at 365 days of follow-up (885 patients [9.8%] vs. 944 patients [10.5%]; hazard ratio, 0.93; 95% CI, 0.85 to 1.02). The percentage of patients with adverse events was similar in the two groups; a higher number of hypersensitivity events was reported in the CSL112 group., Conclusions: Among patients with acute myocardial infarction, multivessel coronary artery disease, and additional cardiovascular risk factors, four weekly infusions of CSL112 did not result in a lower risk of myocardial infarction, stroke, or death from cardiovascular causes than placebo through 90 days. (Funded by CSL Behring; AEGIS-II ClinicalTrials.gov number, NCT03473223.)., (Copyright © 2024 Massachusetts Medical Society.)

Objective: Familial hypercholesterolemia (FH) is characterized by elevated levels of low-density lipoprotein cholesterol (LDL-C) and cardiovascular disease (CVD). Although the role of LDL-C in FH has been studied, the contribution of high-density lipoproteins (HDL) to CVD in FH remains unknown. This study aimed at highlighting the role of HDL in FH., Methods: HDL-specific phospholipid efflux (HDL-SPE) assay was developed to predict CVD risk. HDL-SPE was examined in FH patients (n=30) and compared with age- and sex-matched non-FH controls (n=60)., Results: FH patients had significantly lower HDL-SPE levels (0.90±0.12) than controls (1.12±0.10; p <0.05), despite similar HDL-cholesterol levels in both groups (FH: 57.9±18.7 mg/dl; controls: 57.1±13.8 mg/dl). These differences remained significant after adjusting for confounders., Conclusions: These findings suggest there may be dysfunctionality of HDL in FH., (© 2024 by the Association of Clinical Scientists, Inc.)

HDLs carry sphingosine-1-phosphate (S1P) and stimulate signaling pathways in different cells including macrophages and endothelial cells, involved in atherosclerotic plaque development. HDL signaling via S1P relies on the HDL receptor scavenger receptor class B, type I (SR-B1) and the sphingosine-1-phosphate receptor 1 (S1PR1), which interact when both are heterologously overexpressed in the HEK293 cell line. In this study, we set out to test if SR-B1 and S1PR1 interacted in primary murine macrophages in culture and atherosclerotic plaques. We used knock-in mice that endogenously expressed S1PR1 tagged with eGFP-(S1pr1 eGFP/eGFP mice), combined with proximity ligation analysis to demonstrate that HDL stimulates the physical interaction between SR-B1 and S1PR1 in primary macrophages, that this is dependent on HDL-associated S1P and can be blocked by an inhibitor of SR-B1's lipid transfer activity or an antagonist of S1PR1. We also demonstrate that a synthetic S1PR1-selective agonist, SEW2871, stimulates the interaction between SR-B1 and S1PR1 and that this was also blocked by an inhibitor of SR-B1's lipid transport activity. Furthermore, we detected abundant SR-B1/S1PR1 complexes in atherosclerotic plaques of S1pr1 eGFP/eGFP mice that also lacked apolipoprotein E. Treatment of mice with the S1PR1 antagonist, Ex26, for 12 h disrupted the SR-B1-S1PR1 interaction in atherosclerotic plaques. These findings demonstrate that SR-B1 and S1PR1 form ligand-dependent complexes both in cultured primary macrophages and within atherosclerotic plaques in mice and provide mechanistic insight into how SR-B1 and S1PR1 participate in mediating HDL signaling to activate atheroprotective responses in macrophages., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

High-density lipoproteins (HDLs) are responsible for removing cholesterol from arterial walls, through a process known as reverse cholesterol transport. The main protein in HDL, apolipoprotein A-I (ApoA-I), is essential to this process, and changes in its sequence significantly alter HDL structure and functions. ApoA-I amyloidogenic variants, associated with a particular hereditary degenerative disease, are particularly effective at facilitating cholesterol removal, thus protecting carriers from cardiovascular disease. Thus, it is conceivable that reconstituted HDL (rHDL) formulations containing ApoA-I proteins with functional/structural features similar to those of amyloidogenic variants hold potential as a promising therapeutic approach. Here we explored the effect of protein cargo and lipid composition on the function of rHDL containing one of the ApoA-I amyloidogenic variants G26R or L174S by Fourier transformed infrared spectroscopy and neutron reflectometry. Moreover, small-angle x-ray scattering uncovered the structural and functional differences between rHDL particles, which could help to comprehend higher cholesterol efflux activity and apparent lower phospholipid (PL) affinity. Our findings indicate distinct trends in lipid exchange (removal vs. deposition) capacities of various rHDL particles, with the rHDL containing the ApoA-I amyloidogenic variants showing a markedly lower ability to remove lipids from artificial membranes compared to the rHDL containing the native protein. This effect strongly depends on the level of PL unsaturation and on the particles' ultrastructure. The study highlights the importance of the protein cargo, along with lipid composition, in shaping rHDL structure, contributing to our understanding of lipid-protein interactions and their behavior., (© 2024 The Authors. Protein Science published by Wiley Periodicals LLC on behalf of The Protein Society.)

The high-density lipoprotein (HDL)-associated enzyme paraoxonase 1 (PON1) is expressed almost exclusively in the liver and is then transported by HDL to the peripheral tissues. The lipophilic nature of PON1 enables its easy exchange between the lipoprotein and cell membranes in a process that is dependent on the HDL receptor scavenger receptor class B, type 1 (SR-B1). In endothelial cells, PON1 binding to the cell membrane leads to its internalization by endocytosis and subsequent lysosomal degradation. PON1 is a "promiscuous" enzyme with unusually broad substrate specificity in vitro, but its actual function and substrate are still unknown. The enzyme requires a lipid environment and becomes completely inactive upon delipidation. However, when PON1 binds HDL, its active site faces the lipoprotein's core and is inaccessible to external substrates. Hence, the HDL-bound PON1 is inactive toward substrates outside the particle's lipid core and is rapidly degraded and becomes inactive upon internalization. Consequently, the enzyme is only active in the cell membrane during its transit from HDL to the cytoplasm. To assign a function to PON1, we investigated whether it is a palmitoyl-protein thioesterase (PPT) that can hydrolyze the palmitoyl moieties of membrane proteins involved in HDL and cholesterol transport, such as SR-B1, ABCA1, or their neighboring caveola proteins to facilitate the release of HDL or trigger its endocytosis. This study shows that PON1 can hydrolyze palmitoyl-cysteine thioester bonds in vitro, has direct or indirect PPT activity in vivo, and can significantly decrease the presence of SR-B1 in the endothelial membrane., (© 2023 The Authors. BioFactors published by Wiley Periodicals LLC on behalf of International Union of Biochemistry and Molecular Biology.)

High-density lipoproteins (HDLs) are complex particles with multiple functions. They are thought to have evolved as part of the body's innate defense system against infection. Recent research suggests that HDL levels influence susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the severity of associated complications, making it a promising target for therapeutic intervention., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Serum amyloid A (SAA) is a highly conserved acute-phase protein that plays roles in activating multiple pro-inflammatory pathways during the acute inflammatory response and is commonly used as a biomarker of inflammation. It has been linked to beneficial roles in tissue repair through improved clearance of lipids and cholesterol from sites of damage. In patients with chronic inflammatory diseases, elevated levels of SAA may contribute to increased severity of the underlying condition. The majority of circulating SAA is bound to lipoproteins, primarily high-density lipoprotein (HDL). Interaction with HDL not only stabilizes SAA but also alters its functional properties, likely through altered accessibility of protein-protein interaction sites on SAA. While high-resolution structures for lipid-free, or apo-, forms of SAA have been reported, their relationship with the HDL-bound form of the protein, and with other possible mechanisms of SAA binding to lipids, has not been established. Here, we have used multiple biophysical techniques, including SAXS, TEM, SEC-MALS, native gel electrophoresis, glutaraldehyde crosslinking, and trypsin digestion to characterize the lipid-free and lipid-bound forms of SAA. The SAXS and TEM data show the presence of soluble octamers of SAA with structural similarity to the ring-like structures reported for lipid-free ApoA-I. These SAA octamers represent a previously uncharacterized structure for lipid-free SAA and are capable of scaffolding lipid nanodiscs with similar morphology to those formed by ApoA-I. The SAA-lipid nanodiscs contain four SAA molecules and have similar exterior dimensions as the lipid-free SAA octamer, suggesting that relatively few conformational rearrangements may be required to allow SAA interactions with lipid-containing particles such as HDL. This study suggests a new model for SAA-lipid interactions and provides new insight into how SAA might stabilize protein-lipid nanodiscs or even replace ApoA-I as a scaffold for HDL particles during inflammation., (© 2024 The Authors. Protein Science published by Wiley Periodicals LLC on behalf of The Protein Society.)

Objective: High-density lipoprotein (HDL) has well-characterized anti-atherogenic cholesterol efflux and antioxidant functions. Another function of HDL uncharacterized in rheumatoid arthritis (RA) is its ability to transport microRNAs (miRNAs) between cells and thus alter cellular function. The study's purpose was to determine if HDL-miRNA cargo is altered and affects inflammation in RA., Methods: HDL-microRNAs were characterized in 30 RA and 30 control participants by next generation sequencing and quantitative polymerase chain reaction. The most abundant differentially expressed miRNA was evaluated further. The function of miR-1246 was assessed by miRNA mimics, antagomiRs, small interfering RNA knockdown, and luciferase assays. Monocyte-derived macrophages were treated with miR-1246-loaded HDL and unmodified HDL from RA and control participants to measure delivery of miR-1246 and its effect on interleukin-6 (IL-6)., Results: The most abundant miRNA on HDL was miR-1246; it was significantly enriched two-fold on HDL from RA versus control participants. HDL-mediated miR-1246 delivery to macrophages significantly increased IL6 expression 43-fold. miR-1246 delivery significantly decreased DUSP3 1.5-fold and DUSP3 small interfering RNA knockdown increased macrophage IL6 expression. Luciferase assay indicated DUSP3 is a direct target of miR-1246. Unmodified HDL from RA delivered 1.6-fold more miR-1246 versus control participant HDL. Unmodified HDL from both RA and control participants attenuated activated macrophage IL6 expression, but this effect was significantly blunted in RA so that IL6 expression was 3.4-fold higher after RA versus control HDL treatment., Conclusion: HDL-miR-1246 was increased in RA versus control participants and delivery of miR-1246 to macrophages increased IL-6 expression by targeting DUSP3. The altered HDL-miRNA cargo in RA blunted HDL's anti-inflammatory effect., (© 2023 The Authors. Arthritis & Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

Aims: The entry of lipoproteins from blood into the arterial wall is a rate-limiting step in atherosclerosis. It is controversial whether this happens by filtration or regulated transendothelial transport.Because sphingosine-1-phosphate (S1P) preserves the endothelial barrier, we investigated in vivo and in vitro, whether S1P and its cognate S1P-receptor 3 (S1P3) regulate the transendothelial transport of lipoproteins., Methods and Results: Compared to apoE-haploinsufficient mice (CTRL), apoE-haploinsufficient mice with additional endothelium-specific knock-in of S1P3 (S1P3-iECKI) showed decreased transport of LDL and Evan's Blue but increased transport of HDL from blood into the peritoneal cave. After 30 weeks of high-fat diet feeding, S1P3-iECKI mice had lower levels of non-HDL-cholesterol and less atherosclerosis than CTRL mice. In vitro stimulation with an S1P3 agonist increased the transport of 125I-HDL but decreased the transport of 125I-LDL through human aortic endothelial cells (HAECs). Conversely, inhibition or knock-down of S1P3 decreased the transport of 125I-HDL but increased the transport of 125I-LDL. Silencing of SCARB1 encoding scavenger receptor B1 (SR-BI) abrogated the stimulation of 125I-HDL transport by the S1P3 agonist. The transendothelial transport of 125I-LDL was decreased by silencing of SCARB1 or ACVLR1 encoding activin-like kinase 1 but not by interference with LDLR. None of the three knock-downs prevented the stimulatory effect of S1P3 inhibition on transendothelial 125I-LDL transport., Conclusion: S1P3 regulates the transendothelial transport of HDL and LDL oppositely by SR-BI-dependent and SR-BI-independent mechanisms, respectively. This divergence supports a contention that lipoproteins pass the endothelial barrier by specifically regulated mechanisms rather than passive filtration., Competing Interests: Conflict of interest: none declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Here, we target the high-density lipoprotein (HDL) proteome in a case series of 16 patients with post-COVID-19 symptoms treated with HMG-Co-A reductase inhibitors (statin) plus angiotensin II type 1 receptor blockers (ARBs) for 6 weeks. Patients suffering from persistent symptoms (post-acute sequelae) after serologically confirmed SARS-CoV-2 infection (post-COVID-19 syndrome, PCS, n = 8) or following SARS-CoV-2 vaccination (PVS, n = 8) were included. Asymptomatic subjects with corresponding serological findings served as healthy controls (n = 8/8). HDL was isolated using dextran sulfate precipitation and the HDL proteome of all study participants was analyzed quantitatively by mass spectrometry. Clinical symptoms were assessed using questionnaires before and after therapy. The inflammatory potential of the patients' HDL proteome was addressed in human endothelial cells. The HDL proteome of patients with PCS and PVS showed no significant differences; however, compared to controls, the HDL from PVS/PCS patients displayed significant alterations involving hemoglobin, cytoskeletal proteins (MYL6, TLN1, PARVB, TPM4, FLNA), and amyloid precursor protein. Gene Ontology Biological Process (GOBP) enrichment analysis identified hemostasis, peptidase, and lipoprotein regulation pathways to be involved. Treatment of PVS/PCS patients with statins plus ARBs improved the patients' clinical symptoms. After therapy, three proteins were significantly increased (FAM3C, AT6AP2, ADAM10; FDR < 0.05) in the HDL proteome from patients with PVS/PCS. Exposure of human endothelial cells with the HDL proteome from treated PVS/PCS patients revealed reduced inflammatory cytokine and adhesion molecule expression. Thus, HDL proteome analysis from PVS/PCS patients enables a deeper insight into the underlying disease mechanisms, pointing to significant involvement in metabolic and signaling disturbances. Treatment with statins plus ARBs improved clinical symptoms and reduced the inflammatory potential of the HDL proteome. These observations may guide future therapeutic strategies for PVS/PCS patients.

The Apolipoprotein E gene (APOE) is of great interest due to its role as a risk factor for late-onset Alzheimer's disease. ApoE is secreted by astrocytes in the central nervous system in high-density lipoprotein (HDL)-like lipoproteins. Structural models of lipidated ApoE of high resolution could aid in a mechanistic understanding of how ApoE functions in health and disease. Using monoclonal Fab and F(ab') 2 fragments, we characterize the structure of lipidated ApoE on astrocyte-secreted lipoproteins. Our results provide support for the "double-belt" model of ApoE in nascent discoidal HDL-like lipoproteins, where two ApoE proteins wrap around the nanodisc in an antiparallel conformation. We further show that lipidated, recombinant ApoE accurately models astrocyte-secreted ApoE lipoproteins. Cryogenic electron microscopy of recombinant lipidated ApoE further supports ApoE adopting antiparallel dimers in nascent discoidal lipoproteins., Competing Interests: Declaration of interests D.M.H. is an inventor on a patent licensed by Washington University to NextCure on the therapeutic use of anti-ApoE antibodies. D.M.H. co-founded and is on the scientific advisory board of C2N Diagnostics. D.M.H. is on the scientific advisory board of Denali, Genentech, and Cajal Neuroscience; consults for Asteroid; and is on the advisory board for Cell., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Rationale: Serum amyloid A (SAA) is bound to high-density lipoproteins (HDL) in blood. Although SAA is increased in the blood of patients with asthma, it is not known whether this modifies asthma severity., Objective: We sought to define the clinical characteristics of patients with asthma who have high SAA levels and assess whether HDL from SAA-high patients with asthma is proinflammatory., Methods: SAA levels in serum from subjects with and without asthma were quantified by ELISA. HDLs isolated from subjects with asthma and high SAA levels were used to stimulate human monocytes and were intravenously administered to BALB/c mice., Results: An SAA level greater than or equal to 108.8 μg/mL was defined as the threshold to identify 11% of an asthmatic cohort (n = 146) as being SAA-high. SAA-high patients with asthma were characterized by increased serum C-reactive protein, IL-6, and TNF-α; older age; and an increased prevalence of obesity and severe asthma. HDL isolated from SAA-high patients with asthma (SAA-high HDL) had an increased content of SAA as compared with HDL from SAA-low patients with asthma and induced the secretion of IL-6, IL-1β, and TNF-α from human monocytes via a formyl peptide receptor 2/ATP/P2X purinoceptor 7 axis. Intravenous administration to mice of SAA-high HDL, but not normal HDL, induced systemic inflammation and amplified allergen-induced neutrophilic airway inflammation and goblet cell metaplasia., Conclusions: SAA-high patients with asthma are characterized by systemic inflammation, older age, and an increased prevalence of obesity and severe asthma. HDL from SAA-high patients with asthma is proinflammatory and, when intravenously administered to mice, induces systemic inflammation, and amplifies allergen-induced neutrophilic airway inflammation. This suggests that systemic inflammation induced by SAA-high HDL may augment disease severity in asthma., (Published by Elsevier Inc.)

Background: Atrial fibrillation (AF) is the most common heart arrhythmia and considered to be a progressive chronic disease associated with increased morbidity and mortality. Recent data suggest a link between inflammation, oxidative stress, and AF, although the underlying mechanisms are not fully understood. Because oxidized lipoproteins cause structural damage and electrophysiologic changes in cardiomyocytes, it is feasible that the transformation of atheroprotective high-density lipoprotein (HDL) into dysfunctional HDL contributes to the development of AF., Objective: The purpose of this study was to determine whether a reduced antioxidant function of HDL is associated with the presence of AF., Methods: In this multicenter cross-sectional cohort study, we assessed HDL function in sera of 1206 participants. Patients were divided into groups according to the presence of AF (n = 233) or no AF (n = 973). A validated cell-free biochemical assay was used to determine reduced HDL antioxidant function as assessed by increased normalized HDL lipid peroxide content (nHDL ox )., Results: Participants with AF had a 9% higher mean relative nHDL ox compared to persons without AF (P = .025). nHDL ox was strongly associated with AF in all models of logistic regression, including the analysis adjusted for age, sex, and risk factors for AF (all P ≤.01)., Conclusion: Reduced antioxidant HDL function is associated with the presence of AF, which supports growing evidence that impaired lipoprotein function is linked to electrophysiological changes in cardiomyocytes. nHDL ox is one of several contributors to the initiation and perpetuation of AF., (Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Atherosclerosis results from the deposition and oxidation of LDL and immune cell infiltration in the sub-arterial space leading to arterial occlusion. Studies have shown that transcytosis transports circulating LDL across endothelial cells lining blood vessels. LDL transcytosis is initiated by binding to either scavenger receptor B1 (SR-B1) or activin A receptor-like kinase 1 on the apical side of endothelial cells leading to its transit and release on the basolateral side. HDL is thought to partly protect individuals from atherosclerosis due to its ability to remove excess cholesterol and act as an antioxidant. Apolipoprotein A1 (APOA1), an HDL constituent, can bind to SR-B1, raising the possibility that APOA1/HDL can compete with LDL for SR-B1 binding, thereby limiting LDL deposition in the sub-arterial space. To examine this possibility, we used in vitro approaches to quantify the internalization and transcytosis of fluorescent LDL in coronary endothelial cells. Using microscale thermophoresis and affinity capture, we find that SR-B1 and APOA1 interact and that binding is enhanced when using the cardioprotective variant of APOA1 termed Milano (APOA1-Milano). In male mice, transiently increasing the levels of HDL reduced the acute deposition of fluorescently labeled LDL in the atheroprone inner curvature of the aorta. Reduced LDL deposition was also observed when increasing circulating wild-type APOA1 or the APOA1-Milano variant, with a more robust inhibition from the APOA1-Milano. The results suggest that HDL may limit SR-B1-mediated LDL transcytosis and deposition, adding to the mechanisms by which it can act as an atheroprotective particle., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interests with the contents of this article., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Angiopoietin-like protein 3 (ANGPTL3) is a plasmatic protein that plays a crucial role in lipoprotein metabolism by inhibiting the lipoprotein lipase (LPL) and the endothelial lipase (EL) responsible for the hydrolysis of phospholipids on high-density lipoprotein (HDL). Interest in developing new pharmacological therapies aimed at inhibiting ANGPTL3 has been growing due to the hypolipidemic and antiatherogenic profile observed in its absence. The goal of this study was the in silico characterization of the interaction between ANGPTL3 and EL. Because of the lack of any structural information on both the trimeric coiled-coil N-terminal domain of ANGPTL3 and the EL homodimer as well as data regarding their interactions, the first step was to obtain the three-dimensional model of these two proteins. The models were then refined via molecular dynamics (MD) simulations and used to investigate the interaction mechanism. The analysis of interactions in different docking poses and their refinement via MD allowed the identification of three specific glutamates of ANGPTL3 that recognize a positively charged patch on the surface of EL. These ANGPTL3 key residues, i.e., Glu154, Glu157, and Glu160, could form a putative molecular recognition site for EL. This study paves the way for future investigations aimed at confirming the recognition site and at designing novel inhibitors of ANGPTL3.

Background: Cholesterol efflux capacity (CEC) predicts cardiovascular disease independently of high-density lipoprotein (HDL) cholesterol levels. Isolated small HDL particles are potent promoters of macrophage CEC by the ABCA1 (ATP-binding cassette transporter A1) pathway, but the underlying mechanisms are unclear., Methods: We used model system studies of reconstituted HDL and plasma from control and lecithin-cholesterol acyltransferase (LCAT)-deficient subjects to investigate the relationships among the sizes of HDL particles, the structure of APOA1 (apolipoprotein A1) in the different particles, and the CECs of plasma and isolated HDLs., Results: We quantified macrophage and ABCA1 CEC of 4 distinct sizes of reconstituted HDL. CEC increased as particle size decreased. Tandem mass spectrometric analysis of chemically cross-linked peptides and molecular dynamics simulations of APOA1, the major protein of HDL, indicated that the mobility of C-terminus of that protein was markedly higher and flipped off the surface in the smallest particles. To explore the physiological relevance of the model system studies, we isolated HDL from LCAT-deficient subjects, whose small HDLs (like reconstituted HDLs) are discoidal and composed of APOA1, cholesterol, and phospholipid. Despite their very low plasma levels of HDL particles, these subjects had normal CEC. In both the LCAT-deficient subjects and control subjects, the CEC of isolated extra-small HDL (a mixture of extra-small and small HDL by calibrated ion mobility analysis) was 3- to 5-fold greater than that of the larger sizes of isolated HDL. Incubating LCAT-deficient plasma and control plasma with human LCAT converted extra-small and small HDL particles into larger particles, and it markedly inhibited CEC., Conclusions: We present a mechanism for the enhanced CEC of small HDLs. In smaller particles, the C-termini of the 2 antiparallel molecules of APOA1 are "flipped" off the lipid surface of HDL. This extended conformation allows them to engage with ABCA1. In contrast, the C-termini of larger HDLs are unable to interact productively with ABCA1 because they form a helical bundle that strongly adheres to the lipid on the particle. Enhanced CEC, as seen with the smaller particles, predicts decreased cardiovascular disease risk. Thus, extra-small and small HDLs may be key mediators and indicators of the cardioprotective effects of HDL., Competing Interests: Disclosures K.E.B. serves on the Scientific Advisory Board of Esperion Therapeutics. The other authors report no conflicts.

Adenosine (ADO) is a common chemotherapy-associated immune checkpoint that hinders anti-tumor immunity-mediated efficacy of chemotherapy. Herein, we created a synthetic high-density lipoprotein (sHDL) by co-assembly of a doxorubicin (DOX)-apolipoprotein A1 mimetic peptide conjugate, PSB-603 (an A2BR inhibitor), phospholipid, and cholesterol oleate with a microfluidic-based method. The obtained DP-sHDL showed a self-promoted drug delivery to cancer cells via remodeling tumor microenvironment. DP-sHDL could trigger the release of ATP from cancer cells and inhibit its conversion into ADO. Consequently, DP-sHDL, while increasing immunogenic cell death, reduced intratumoral ADO levels by 58%. This treatment improved both the density and activity of CD8 + T cells as well as NK cells and relieved the immunosuppressive microenvironment, and led to a substantial inhibition of 4T1 tumor growth, thereby extending the survival of mice. The efficacy of DP-sHDL could be further improved when used in combination with immune checkpoint blockade therapy. We envision that this platform provides a simple yet promising strategy to enhance anti-tumor response of chemotherapy by relieving treatment-associated immunosuppression., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

High-density lipoprotein (HDL) cholesterol is a well-known biomarker, which has been associated with reduction in the risk of cardiovascular diseases (CVD). However, some HDL anti-atherosclerotic functions may be impaired without altered HDL-cholesterol (HDL-C) level via its dysfunctional proteins or other physiological reactions in vivo. We previously showed that activated mast cell-derived chymase could modestly cleave apolipoprotein A-I (apoA-I) in HDL 3, and further easily cleave lipid-free apoA-I. In contrast, myeloperoxidase (MPO) secreted by macrophages, the main cell type in atherosclerotic plaques, could oxidize HDL proteins, which might modify their tertiary structures, increasing their susceptibility to other enzymes. Here we focused on the co-modification and impact of chymase and MPO, usually secreted during inflammation from cells with possible co-existence in atheromas, on HDL. Only after sequential treatment with MPO and then chymase, two novel truncated apoA-I fragments were generated from HDL. One fragment was 16.5 kDa, and the cleavage site by chymase after MPO modification was the C-terminal of Tyr 100 in apoA-I, cross-validated by three different mass spectrometry methods. This novel apoA-I fragment can be trapped in HDL particles to avoid kidney glomerular filtration and has a specific site for antibody generation for ELISA tests. As such, its quantification can be useful in predicting patients with CVD having normal HDL-C levels., Competing Interests: Declaration of competing interest The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (Copyright © 2023 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)

Cardiovascular diseases (CVDs) have become the leading global cause of mortality, prompting a heightened focus on identifying precise indicators for their assessment and treatment. In this perspective, the plasma levels of HDL have emerged as a pivotal focus, given the demonstrable correlation between plasma levels and cardiovascular events, rendering them a noteworthy biomarker. However, it is crucial to acknowledge that HDLs, while intricate, are not presently a direct therapeutic target, necessitating a more nuanced understanding of their dynamic remodeling throughout their life cycle. HDLs exhibit several anti-atherosclerotic properties that define their functionality. This functionality of HDLs, which is independent of their concentration, may be impaired in certain risk factors for CVD. Moreover, because HDLs are dynamic parameters, in which HDL particles present different atheroprotective properties, it remains difficult to interpret the association between HDL level and CVD risk. Besides the antioxidant and anti-inflammatory activities of HDLs, their capacity to mediate cholesterol efflux, a key metric of HDL functionality, represents the main anti-atherosclerotic property of HDL. In this review, we will discuss the HDL components and HDL structure that may affect their functionality and we will review the mechanism by which HDL mediates cholesterol efflux. We will give a brief examination of the effects of aging and diet on HDL structure and function.

High-density lipoprotein (HDL) nanoparticles promote endothelial cell (EC) function and suppress inflammation, but their utility in treating EC dysfunction has not been fully explored. Here, we describe a fusion protein named ApoA1-ApoM (A1M) consisting of apolipoprotein A1 (ApoA1), the principal structural protein of HDL that forms lipid nanoparticles, and ApoM, a chaperone for the bioactive lipid sphingosine 1-phosphate (S1P). A1M forms HDL-like particles, binds to S1P, and is signaling competent. Molecular dynamics simulations showed that the S1P-bound ApoM moiety in A1M efficiently activated EC surface receptors. Treatment of human umbilical vein ECs with A1M-S1P stimulated barrier function either alone or cooperatively with other barrier-enhancing molecules, including the stable prostacyclin analog iloprost, and suppressed cytokine-induced inflammation. A1M-S1P injection into mice during sterile inflammation suppressed neutrophil influx and inflammatory mediator secretion. Moreover, systemic A1M administration led to a sustained increase in circulating HDL-bound S1P and suppressed inflammation in a murine model of LPS-induced endotoxemia. We propose that A1M administration may enhance vascular endothelial barrier function, suppress cytokine storm, and promote resilience of the vascular endothelium.

We previously demonstrated that normal high-density lipoprotein (nHDL) can promote angiogenesis, whereas HDL from patients with coronary artery disease (dHDL) is dysfunctional and impairs angiogenesis. Autophagy plays a critical role in angiogenesis, and HDL regulates autophagy. However, it is unclear whether nHDL and dHDL regulate angiogenesis by affecting autophagy. Endothelial cells (ECs) were treated with nHDL and dHDL with or without an autophagy inhibitor. Autophagy, endothelial nitric oxide synthase (eNOS) expression, miRNA expression, nitric oxide (NO) production, superoxide anion (O 2 •- ) generation, EC migration, and tube formation were evaluated. nHDL suppressed the expression of miR-181a-5p, which promotes autophagy and the expression of eNOS, resulting in NO production and the inhibition of O 2 •- generation, and ultimately increasing in EC migration and tube formation. dHDL showed opposite effects compared to nHDL and ultimately inhibited EC migration and tube formation. We found that autophagy-related protein 5 (ATG5) was a direct target of miR-181a-5p. ATG5 silencing or miR-181a-5p mimic inhibited nHDL-induced autophagy, eNOS expression, NO production, EC migration, tube formation, and enhanced O 2 •- generation, whereas overexpression of ATG5 or miR-181a-5p inhibitor reversed the above effects of dHDL. ATG5 expression and angiogenesis were decreased in the ischemic lower limbs of hypercholesterolemic low-density lipoprotein receptor null (LDLr -/- ) mice when compared to C57BL/6 mice. ATG5 overexpression improved angiogenesis in ischemic hypercholesterolemic LDLr -/- mice. Taken together, nHDL was able to stimulate autophagy by suppressing miR-181a-5p, subsequently increasing eNOS expression, which generated NO and promoted angiogenesis. In contrast, dHDL inhibited angiogenesis, at least partially, by increasing miR-181a-5p expression, which decreased autophagy and eNOS expression, resulting in a decrease in NO production and an increase in O 2 •- generation. Our findings reveal a novel mechanism by which HDL affects angiogenesis by regulating autophagy and provide a therapeutic target for dHDL-impaired angiogenesis., (© 2023. Science China Press.)

Hepatitis C virus (HCV) is a member of the Flaviviridae family; however, unlike other family members, the HCV virion has an unusually high lipid content. HCV has two envelope glycoproteins, E1 and E2. E2 contributes to receptor binding, cell membrane attachment, and immune evasion. In contrast, the functions of E1 are poorly characterized due, in part, to challenges in producing the protein. This manuscript describes the expression and purification of a soluble E1 ectodomain (eE1) that is recognized by conformational, human monoclonal antibodies. eE1 forms a complex with apolipoproteins AI and AII, cholesterol, and phospholipids by recruiting high-density lipoprotein (HDL) from the extracellular media. We show that HDL binding is a function specific to eE1 and HDL hinders recognition of E1 by a neutralizing monoclonal antibody. Either low-density lipoprotein or HDL increases the production and infectivity of cell culture-produced HCV, but E1 preferentially selects HDL, influencing both viral life cycle and antibody evasion.IMPORTANCEHepatitis C virus (HCV) infection is a significant burden on human health, but vaccine candidates have yet to provide broad protection against this infection. We have developed a method to produce high quantities of soluble E1 or E2, the viral proteins located on the surface of HCV. HCV has an unusually high lipid content due to the recruitment of apolipoproteins. We found that E1 (and not E2) preferentially recruits host high-density lipoprotein (HDL) extracellularly. This recruitment of HDL by E1 prevents binding of E1 by a neutralizing antibody and furthermore prevents antibody-mediated neutralization of the virus. By comparison, low-density lipoprotein does not protect the virus from antibody-mediated neutralization. Our findings provide mechanistic insight into apolipoprotein recruitment, which may be critical for vaccine development., Competing Interests: The authors declare no conflict of interest.