Synthetic High-density Lipoprotein Research Articles

Synthetic high-density lipoprotein (sHDL): a bioinspired nanotherapeutics for managing periapical bone inflammation

Apical periodontitis (AP) is a dental-driven condition caused by pathogens and their toxins infecting the inner portion of the tooth (i.e., dental pulp tissue), resulting in inflammation and apical bone resorption affecting 50% of the worldwide population, with more than 15 million root canals performed annually in the United States. Current treatment involves cleaning and decontaminating the infected tissue with chemo-mechanical approaches and materials introduced years ago, such as calcium hydroxide, zinc oxide–eugenol, or even formalin products. Here, we present, for the first time, a nanotherapeutics based on using synthetic high-density lipoprotein (sHDL) as an innovative and safe strategy to manage dental bone inflammation. sHDL application in concentrations ranging from 25 µg to 100 µg/mL decreases nuclear factor Kappa B (NF-κB) activation promoted by an inflammatory stimulus (lipopolysaccharide, LPS). Moreover, sHDL at 500 µg/mL concentration markedly decreases in vitro osteoclastogenesis (P < 0.001), and inhibits IL-1α (P = 0.027), TNF-α (P = 0.004), and IL-6 (P < 0.001) production in an inflammatory state. Notably, sHDL strongly dampens the Toll-Like Receptor signaling pathway facing LPS stimulation, mainly by downregulating at least 3-fold the pro-inflammatory genes, such as Il1b, Il1a, Il6, Ptgs2, and Tnf. In vivo, the lipoprotein nanoparticle applied after NaOCl reduced bone resorption volume to (1.3 ± 0.05) mm3 and attenuated the inflammatory reaction after treatment to (1 090 ± 184) cells compared to non-treated animals that had (2.9 ± 0.6) mm3 (P = 0.012 3) and (2 443 ± 931) cells (P = 0.004), thus highlighting its promising clinical potential as an alternative therapeutic for managing dental bone inflammation.

Chemical conjugation mitigates immunotoxicity of chemotherapy via reducing receptor-mediated drug leakage from lipid nanoparticles.

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 (ED-sHDL) or chemically conjugated (CD-sHDL) DM1. We found that CD-sHDL showed less accumulation in the tumor draining lymph nodes (DLNs) and femur, resulting in a lower toxicity against myeloid cells than ED-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 CD-sHDL, leading to a better efficacy and immune memory of CD-sHDL against colon cancer. Furthermore, liposomes with conjugated DM1 (CD-Lipo) showed lower immunotoxicity than those with entrapped drug (ED-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.

Type 2 Diabetes and HDL Dysfunction: A Key Contributor to Glycemic Control.

High-density lipoproteins (HDL) have been shown to exert multiple cardioprotective and antidiabetic functions, such as their ability to promote cellular cholesterol efflux and their antioxidant, anti-inflammatory, and antiapoptotic properties. Type 2 diabetes (T2D) is usually associated with low high-density lipoprotein cholesterol (HDL-C) levels as well as with significant alterations in the HDL composition, thereby impairing its main functions. HDL dysfunction also negatively impacts both pancreatic β-cell function and skeletal muscle insulin sensitivity, perpetuating this adverse self-feeding cycle. The impairment of these pathways is partly dependent on cellular ATP-binding cassette transporter (ABC) A1-mediated efflux to lipid-poor apolipoprotein (apo) A-I in the extracellular space. In line with these findings, experimental interventions aimed at improving HDL functions, such as infusions of synthetic HDL or lipid-poor apoA-I, significantly improved glycemic control in T2D patients and experimental models of the disease. Cholesteryl ester transfer protein (CETP) inhibitors are specific drugs designed to increase HDLC and HDL functions. Posthoc analyses of large clinical trials with CETP inhibitors have demonstrated their potential anti-diabetic properties. Research on HDL functionality and HDL-based therapies could be a crucial step toward improved glycemic control in T2D subjects.

Preparation and in vitro evaluation of synthetic high-density lipoproteins as parenteral drug delivery system for tamoxifen citrate

The aim of this study was to develop a bioinspired drug delivery system for tamoxifen citrate (TC) based on synthetic high density lipoproteins (sHDL). For this purpose, sHDL nanoparticles were prepared from a mimetic peptide (5A peptide) and different lipids using thin film hydration method followed by sonication and thermal cycling. Various formulation parameters including lipid composition, lipid to peptide ratio, and drug to carrier ratio had a remarkable impact on the properties and the release pattern of the nanoparticles. The optimized formula (F14) displayed a spherical morphology, average diameter of (35.7±12.4) nm, and a zeta potential (ζ) equals to (-48.4± 0.5) mV. The encapsulation efficiency and drug loading of F14 were (96.5±0.7%) and (9.65±0.1%), respectively. Besides, F14 showed a good stability in human plasma for 24 hours. The encapsulation of the lipophilic drug within the hydrophobic core of the nanocarrier enabled a slow drug release from nanoparticles which follows a near zero order controlled mechanism. The promising results of this study opens an avenue for using sHDL as a delivery system for administration of TC intravenously. Therefore, the optimized formula is suggested to be subject for future analyses in terms of in vitro cytotoxicity against breast cancer cells and in vivo evaluation in tumor bearing animals.

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.

Synthetic High-Density Lipoprotein-Based Nanomedicine to Silence SOCS1 in Tumor Microenvironment and Trigger Antitumor Immunity against Glioma.

Immunotherapies have shed light on the treatment of many cancers, but have not improved the outcomes of glioma (GBM). Here, we demonstrated that suppressor of cytokine signaling 1 (SOCS1) was associated with the GBM-associated immunosuppression and developed a multifunctional nanomedicine, which silenced SOCS1 in the tumor microenvironment (TME) of GBM and triggered strong antitumor immunity against GBM. Synthetic high-density lipoprotein (sHDL) was selected as the nanocarrier and a peptide was used to facilitate the blood-brain-barrier (BBB) penetration. The nanocarrier was loaded with a small interfering RNA (siRNA), a peptide, and an adjuvant to trigger antitumor immunity. The nanomedicine concentrated on the TME in vivo, further promoting dendritic cell maturation and T cell proliferation, triggering strong cytotoxic T lymphocyte responses, and inhibiting tumor growth. Our work provides an alternative strategy to simultaneously target and modulate the TME in GBM patients and points to an avenue for enhancing the efficacy of immunotherapeutics.

Enhancement of Anti-inflammatory Effects of Synthetic High-Density Lipoproteins by Incorporation of Anionic Lipids.

Phosphatidylserine (PS) is an anionic phospholipid component in endogenous high-density lipoprotein (HDL). With the intrinsic anti-inflammatory effects of PS and the correlation between PS content and HDL functions, it was hypothesized that incorporating PS would enhance the therapeutic effects of HDL mimetic particles. To test this hypothesis, a series of synthetic high-density lipoproteins (sHDLs) were prepared with an apolipoprotein A-I (ApoA-1) mimetic peptide, 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC), and 1-palmitoyl-2-oleoyl-glycero-3-phospho-l-serine (POPS). Incorporating PS was found to improve the particle stability of sHDLs. Moreover, increasing the PS content in sHDLs enhanced the anti-inflammatory effects on lipopolysaccharide-activated macrophages and endothelial cells. The incorporation of PS had no negative impact on cholesterol efflux capacity, in vivo cholesterol mobilization, and did not affect the pharmacokinetic profiles of sHDLs. Such results suggest the therapeutic potential of PS-containing sHDLs for inflammation resolution in atherosclerosis and other inflammatory diseases.

Apolipoprotein-mimetic nanodiscs reduce lipid accumulation and improve liver function in acid sphingomyelinase deficiency

Acid sphingomyelinase deficiency (ASMD) is a severe lipid storage disorder caused by the diminished activity of the acid sphingomyelinase enzyme. ASMD is characterized by the accumulation of sphingomyelin in late endosomes and lysosomes leading to progressive neurological dysfunction and hepatosplenomegaly. Our objective was to investigate the utility of synthetic apolipoprotein A-I (ApoA-I) mimetics designed to act as lipid scavengers for the treatment of ASMD. We determined the lead peptide, 22A, could reduce sphingomyelin accumulation in ASMD patient skin fibroblasts in a dose dependent manner. Intraperitoneal administration of 22A formulated as a synthetic high-density lipoprotein (sHDL) nanodisc mobilized sphingomyelin from peripheral tissues into circulation and improved liver function in a mouse model of ASMD. Together, our data demonstrates that apolipoprotein mimetics could serve as a novel therapeutic strategy for modulating the pathology observed in ASMD.

Manipulating Neovasculature-Targeting Capability of Biomimetic Nanodiscs for Synergistic Photoactivatable Tumor Infarction and Chemotherapy.

Tumor infarction therapy is a promising antitumor strategy with the advantages of taking a short therapy duration, less risk of resistance, and effectiveness against a wide range of tumor types. However, its clinical application is largely hindered by tumor recurrence in the surviving rim and the potential risk of thromboembolic events due to nonspecific vasculature targeting. Herein, a neovasculature-targeting synthetic high-density lipoprotein (sHDL) nanodisc loaded with pyropheophorbide-a and camptothecin (CPN) was fabricated for photoactivatable tumor infarction and synergistic chemotherapy. By manipulating the anisotropy in ligand modification of sHDL nanodiscs, CPN modified with neovaculature-targeting peptide on the planes (PCPN) shows up to 7-fold higher cellular uptake compared with that around the edge (ECPN). PCPN can efficiently bind to endothelial cells of tumor vessels, and upon laser irradiation, massive local thrombus can be induced by the photodynamic reaction to deprive nutrition supply. Meanwhile, CPT could be released in response to the tumor reductive environment, thus killing residual tumor cells in the surviving rim to inhibit recurrence. These findings not only offer a powerful approach of synergistic cancer therapy but also suggest the potential of plane-modified sHDL nanodiscs as a versatile drug delivery nanocarrier.

Gemcitabine-loaded synthetic high-density lipoprotein preferentially eradicates hepatic monocyte-derived macrophages in mouse liver with colorectal cancer metastases.

Liver metastasis of colorectal cancer (CRC) is the critical cause of CRC-related death due to its unique immunosuppressive microenvironment. In this study we generated a gemcitabine-loaded synthetic high-density lipoprotein (G-sHDL) to reverse immunosuppression in livers with CRC metastases. After intravenous injection, sHDL targeted hepatic monocyte-derived alternatively activated macrophages (Mono-M2) in the livers of mice bearing both subcutaneous tumors and liver metastases. The G-sHDL preferentially eradicated Mono-M2 in the livers with CRC metastases, which consequently prevented Mono-M2-mediated killing of tumor antigen-specific CD8+ T cells in the livers and thus improved the densities of tumor antigen-specific CD8+ T cells in the blood, tumor-draining lymph nodes and subcutaneous tumors of the treated mice. While reversing the immunosuppressive microenvironment, G-sHDL also induced immunogenic cell death of cancer cells, promoted maturation of dendritic cells, and increased tumor infiltration and activity of CD8+ T cells. Collectively, G-sHDL inhibited the growth of both subcutaneous tumors and liver metastases, and prolonged the survival of animals, which could be further improved when used in conjunction with anti-PD-L1 antibody. This platform can be a generalizable platform to modulate immune microenvironment of diseased livers.

Tamoxifen Citrate- loaded synthetic high-density lipoproteins: Assessment of cellular toxicity in breast cancer cells

Tamoxifen Citrate (TC) is the standard endocrine therapy for estrogen receptor (ER) positive breast cancer. TC is a selective estrogen receptor modulator (SERM) whose estrogenic properties in uterus have been linked to increased side&#x0D; effects like blood clots, endometrial polyps and cancer. Therefore, significant amount of research has been carried out to develop tamoxifen loaded nano-formulations with a preferential accumulation in tumor tissue rather than healthy tissues.&#x0D; Synthetic high-density lipoproteins (sHDL) are novel nanocarriers with inherent active-targeting ability towards tumor cells through the ligand–receptor interaction between apolipoprotein A-I (Apo A-I) and scavenger receptor class B type I (SR-BI) overexpressed in various malignant cells. The current study was carried out to investigate whether encapsulation of TC in sHDL could improve the cytotoxic effect of TC against malignant cells. For this purpose, the cytotoxicity of TC-sHDL was evaluated in MCF-7 cell line in vitro. MTT assay demonstrated the increased cytotoxicity of TC-sHDL against cancer cells as compared with the cytotoxic effect of the free drug.

Systematic evaluation of the effect of different apolipoprotein A-I mimetic peptides on the performance of synthetic high-density lipoproteins in vitro and in vivo

Synthetic high-density lipoproteins nanomedicine (sHDL) composed of apolipoprotein A-I (ApoA-I) mimetic peptides and lipids have shown very promising results for the treatment of various cardiovascular diseases. Numerous efforts have also been made to design different ApoA-I mimetic peptides to improve the potency of sHDL, especially the efficiency of reverse cholesterol transport. However, the way in which ApoA-I mimetic peptides affect the properties of sHDL, including stability, cholesterol efflux, cholesterol esterification, elimination in vivo, and the relationship of these properties, is still poorly understood. Revealing the effect of these factors on the potency of sHDL is important for the design of better ApoA-I mimetic peptides. In this study, three widely used ApoA-I mimetic peptides with different sequences, lengths, LCAT activation and lipid binding affinities were used for the preparation of sHDL and were evaluated in terms of physical/chemical properties, cholesterol efflux, cholesterol esterification, remodeling, and pharmacokinetics/pharmacodynamics. Our results showed that ApoA-I mimetic peptides with the highest cholesterol efflux and cholesterol esterification in vitro did not exhibit the highest cholesterol mobilization in vivo. Further analysis indicated that other factors, such as pharmacokinetics and remodeling of sHDL, need to be considered in order to predict the efficiency of cholesterol mobilization in vivo. Thus, our study highlights the importance of using the overall performance, rather than in vitro results alone, as the blueprint for the design and optimization of ApoA-I mimetic peptides.

Cancer stem cell antigen nanodisc cocktail elicits anti-tumor immune responses in melanoma.

One of the major reasons for poor cancer outcomes is the existence of cancer stem cells (CSCs). CSCs are a small subpopulation of tumor cells that can self-renew, differentiate into the majority of tumor cells, and maintain tumorigenicity. As CSCs are resistant to traditional chemotherapy and radiation, they contribute to metastasis and relapse. Thus, new approaches are needed to target and eliminate CSCs. Here, we sought to target and reduce the frequency of CSCs in melanoma by therapeutic vaccination against CSC-associated transcription factors, such as Sox2 and Nanog, and aldehyde dehydrogenase (ALDH). Toward this goal, we have identified novel immunogenic peptide epitopes derived from CSC-associated Sox2 and Nanog and synthesized synthetic high-density lipoprotein (sHDL) nanodisc vaccine formulated with Sox2, Nanog, and ALDH antigen peptides together with CpG, a Toll-like receptor 9 agonist. Vaccination with nanodiscs containing six CSC antigen peptides elicited robust T cell responses against CSC-associated antigens and promoted intratumoral infiltration of CD8+ T cells, while reducing the frequency of CSCs and CD4+ regulatory T cells within melanoma tumors. Nanodisc vaccination effectively reduced tumor growth and significantly extended animal survival without toxicity toward normal stem cells. Overall, our therapeutic strategy against CSCs represents a cost-effective, safe, and versatile approach that may be applied to melanoma and other cancer types, as well as serve as a critical component in combined therapies to target and eliminate CSCs.

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.

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.

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.

Abstract 495: Effect Of Lipid Composition On The Atheroprotective Properties Of High-Density Lipoprotein-Mimicking Micelles

An imbalance of cholesterol metabolism and unresolved local inflammation on the arterial wall drives atherosclerosis progression. Synthetic high-density lipoproteins (sHDL) have been shown to promote reverse cholesterol transport and reduce vascular inflammation, but producing sHDL at a large scale is challenging due to the difficulty in manufacturing recombinant Apolipoprotein A-I. HDL-mimicking micelles have been designed to mimic the structure and function of HDL. Prior research has shown that the phospholipid (PL) composition of HDL affects its overall activity, thus we have examined how PL composition of micelles affects it’s anti-inflammatory properties and cholesterol mobilization capacity. Micelles were composed four phosphatylcolines (PC), either POPC, DMPC, DPPC or DSPC, and DSPE-PEG2k. A second library of micelles was created using different ratios of DMPC and DSPE-PEG. Micelles ranged from 14 to 28 nm in diameter in size. In vitro , POPC and DMPC micelles were able to reduce TNF-α and IL-6 cytokine levels, diminish activation of nuclear factor-κB (NF-κB) and dissolve cholesterol crystals to a greater extent than DPPC and DSPC micelles. 1:2 DMPC:DSPE-PEG micelles caused the greatest percentage of cholesterol effuxed from cells (~8%) . In vivo PK/PD results showed that the PC composition does not greatly affect the PK or cholesterol mobilization of micelles. On the contrary, micelles with a 1:3 DMPC:DSPE-PEG ratio had a larger AUC (22815.2 mg*h/dL) and C max (775.0 mg/dL) when compared to the 1:0.5 ratio micelles (14266.1 mg*h/dL and 523.2 mg/dL, respectively). The maximum amount of cholesterol mobilized over 48 hours was also greater in the 1:3 ratio vs 1:0.5 ratio micelles (7813.3 mg*h/dL vs 3883.3 mg*h/dL). In conclusion, the composition of HDL-mimicking micelles affects it’s in vitro anti-atherosclerotic properties, such as reduction of pro-inflammatory cytokine release, diminished activation of NF-kB, cholesterol crystal dissolution and cholesterol efflux capabilities, as well as cholesterol mobilization in vivo . Further investigation must be completed in order to fully understand how lipid properties influence the therapeutic potential of micelles to treat atherosclerosis.

Lenvatinib- and vadimezan-loaded synthetic high-density lipoprotein for combinational immunochemotherapy of metastatic triple-negative breast cancer

Metastatic triple-negative breast cancer (TNBC) is the most aggressive type of breast cancer. Combination of systemic chemotherapy and immune checkpoint blockade is effective but of limited benefit due to insufficient intratumoral infiltration of cytotoxic T lymphocytes (CTLs) and the accumulation of immunosuppressive cells. Herein, we designed a lenvatinib- and vadimezan-loaded synthetic high-density lipoprotein (LV-sHDL) for combinational immunochemotherapy of metastatic TNBC. The LV-sHDL targeted scavenger receptor class B type 1-overexpressing 4T1 cells in the tumor after intravenous injection. The multitargeted tyrosine kinase inhibitor (TKI) lenvatinib induced immunogenic cell death of the cancer cells, and the stimulator of interferon genes (STING) agonist vadimezan triggered local inflammation to facilitate dendritic cell maturation and antitumor macrophage differentiation, which synergistically improved the intratumoral infiltration of total and active CTLs by 33- and 13-fold, respectively. LV-sHDL inhibited the growth of orthotopic 4T1 tumors, reduced pulmonary metastasis, and prolonged the survival of animals. The efficacy could be further improved when LV-sHDL was used in combination with antibody against programmed cell death ligand 1. This study highlights the combination use of multitargeted TKI and STING agonist a promising treatment for metastatic TNBC.

APOA1: a Protein with Multiple Therapeutic Functions.

Apolipoprotein (APO) A1, the main apolipoprotein of plasma high-density lipoproteins (HDLs), has several well documented cardioprotective functions. A number of additional potentially beneficial functions of APOA1 have recently been identified. This review is concerned with the therapeutic potential of all of these functions in multiple disease states. Knowledge of the beneficial functions of APOA1 in atherosclerosis, thrombosis, diabetes, cancer, and neurological disorders is increasing exponentially. These insights have led to the development of clinically relevant peptides and APOA1-containing, synthetic reconstituted HDL (rHDL) preparations that mimic the functions of full-length APOA1. APOA1 is a multifunctional apolipoprotein that has therapeutic potential in several diseases. Translation of this knowledge into the clinic is likely to be dependent on the efficacy and bioavailability of small peptides and synthetic rHDL preparations that are currently under investigation, or in development.

High-density lipoprotein modulates tumor-associated macrophage for chemoimmunotherapy of hepatocellular carcinoma

Intratumoral abundance of alternatively activated macrophages (M2) in hepatocellular carcinoma (HCC) is associated with advanced stages, poor prognosis and failure of checkpoint blockade immunotherapy. In this work, we discover that synthetic high-density lipoproteins (sHDLs) preferentially deliver cargoes into M2 and Hepa1–6 HCC cells, based on which finding we create a functional sHDL containing esterase-responsive prodrugs of vadimezan and gemcitabine (VG-sHDLs). The VG-sHDLs induce the HCC cells to release damage-associated molecular patterns (high mobility group box 1 protein and ATP) and cytokines including macrophage colony stimulating factor and type I interferons, improving monocyte differentiation into classically activated macrophages (M1) and dendritic cells. Meanwhile, the VG-sHDLs kill M2 without significant toxicity to M1. After intravenous injection, the VG-sHDLs increase intratumoral M1 as well as proinflammatory molecules such as C-X-C motif ligand 9 and 10 and interleukin 12, but reduce M2 and anti-inflammatory cytokine interleukin 10. These changes enhance the recruitment and activity of cytotoxic T lymphocytes, which eradicate HCC tumors and also establish tumor-specific immune memory that prevents recurrence. This work sheds light on the interactions between sHDL and intratumoral cells, and provides rationale for chemoimmunotherapy of HCC using conventional chemotherapeutics and emerging immune modulators.