Asialoglycoprotein Receptor Research Articles

Fusarolides A-C, Three Pyran-Macrolide Hybrids from a Marine Derived Fungal Fusarium verticillioide G102 as Asialoglycoprotein receptor 1 Inhibitor and Phytopathogenic Fungicides.

Three undescribed 20-membered macrolides, fusarolides A-C (1-3), with relatively rare pyran-macrolide structures and complex chiral centers, were isolated from a marine derived fungal Fusarium verticillioide G102. Their chemical structures and stereoconfigurations were well elaborated. Compound 1 promoted cholesterol efflux from Huh-7 cells in a concentration-dependent manner by inhibiting Asialoglycoprotein receptor 1 (ASGR1), which was identified as a new therapeutic target in hypercholesterolemia in liver. Besides, compounds 1-3 exhibited obvious anti-phytopathogenic fungal activities.

Glycoconjugates of adefovir and tenofovir as asialoglycoprotein-mediated Anti-HBV prodrugs with enhanced liver targeting.

Hepatitis B virus (HBV) infection remains a significant global health challenge, often leading to severe liver complications such as cirrhosis and cancer. Current treatments rely heavily on nucleos(t)ide analogues like adefovir and tenofovir due to their potent antiviral effects. However, their clinical utility is limited by insufficient liver targeting, leading to off-target side effects, particularly nephrotoxicity. To improve liver-specific drug delivery and reduce adverse effects, we designed novel liver-targeted prodrugs by conjugating adefovir and tenofovir with N-acetylgalactosamine (GalNAc) and tris-GalNAc ligands, which have high affinity for the asialoglycoprotein receptor (ASGPR) predominantly expressed in hepatocytes. Four prodrugs (A1, A2, T1, and T2) were synthesized and evaluated for cytotoxicity, maximum tolerated dose, anti-HBV activity, metabolic stability, pharmacokinetics, and liver-targeting properties. The prodrugs exhibited low cytotoxicity, robust anti-HBV activity, and enhanced selectivity compared to their parent drugs. Notably, the tris-GalNAc conjugates A2 and T2 demonstrated superior liver targeting, showing a threefold higher concentration in the liver compared to the kidneys, thus minimizing renal exposure. These findings suggest that GalNAc and tris-GalNAc conjugation is a promising strategy for enhancing the therapeutic efficacy and safety of adefovir and tenofovir, with potential for further optimization as liver-targeted anti-HBV prodrugs.

Small Extracellular Vesicles Engineered Using Click Chemistry to Express Chimeric Antigen Receptors Show Enhanced Efficacy in Acute Liver Failure.

Acetaminophen (APAP) overdose can cause severe liver injury and life-threatening conditions that may lead to multiple organ failure without proper treatment. N-acetylcysteine (NAC) is the accepted and prescribed treatment for detoxification in cases of APAP overdose. Nonetheless, in acute liver failure (ALF), particularly when the ingestion is substantial, NAC may not fully restore liver function. NAC administration in ALF has limitations and potential adverse effects, including nausea, vomiting, diarrhoea, flatus, gastroesophageal reflux, and anaphylactoid reactions. Mesenchymal stromal cell (MSC)-based therapies using paracrine activity show promise for treating ALF, with preclinical studies demonstrating improvement. Recently, MSC-derived extracellular vesicles (EVs) have emerged as a new therapeutic option for liver injury. MSC-derived EVs can contain various therapeutic cargos depending on the cell of origin, participate in physiological processes, and respond to abnormalities. However, most therapeutic EVs lack a distinct orientation upon entering the body, resulting in a lack of targeting specificity. Therefore, enhancing the precision of natural EV delivery systems is urgently needed. Thus, we developed an advanced targeting technique to deliver modified EVs within the body. Our strategy aims to employ bioorthogonal click chemistry to attach a targeting molecule to the surface of small extracellular vesicles (sEVs), creating exogenous chimeric antigen receptor-modified sEVs (CAR-sEVs) for the treatment. First, we engineered azido-modified sEVs (N3-sEVs) through metabolic glycoengineering by treating MSCs with the azide-containing monosaccharide N-azidoacetyl-mannosamine (Ac4ManNAz). Next, we conjugated N3-sEVs with a dibenzocyclooctyne (DBCO)-tagged single-chain variable fragment (DBCO-scFv) that targets the asialoglycoprotein receptor (ASGR1), thus producing CAR-sEVs for precise liver targeting. The efficacy of CAR-sEV therapy in ALF models by targeting ASGR1 was validated. MSC-derived CAR-sEVs reduced serum liver enzymes, mitigated liver damage, and promoted hepatocyte proliferation in APAP-induced injury. Overall, CAR-sEVs exhibited enhanced hepatocyte specificity and efficacy in ameliorating liver injury, highlighting the significant advancements achievable with cell-free targeted therapy.

Targeted Degradation of HCV Polymerase by GalNAc-Conjugated ApTACs for Pan-Genotypic Antiviral Therapy with High Resistance Barriers.

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease. Although interferon-free direct-acting antivirals have led to significant advancements in the treatment of HCV infection, the high genetic variability of the virus and the emergence of acquired drug resistance pose potential threats to their effectiveness. In this study, we develop a broad-spectrum aptamer-based proteolysis targeting chimera, designated dNS5B, which effectively degrades both pan-genotypic NS5B polymerase and drug-resistant mutants through ubiquitin proteasome system. To achieve hepatocyte-specific uptake, we further develop Gal-dNS5B by coupling the dNS5B with a trivalent N-acetylgalactosamine (tri-GalNAc), a ligand for the liver-specific asialoglycoprotein receptor. Gal-dNS5B exclusively accumulates in hepatocytes and suppresses HCV replication by degrading NS5B. Collectively, our research lays the groundwork for a scalable strategy in the development of antiviral medications aimed at addressing current and future challenges posed by hepatitis viruses and other re-emerging viral pandemics.

Whole-Body Physiologically Based Pharmacokinetic Modeling of GalNAc-Conjugated siRNAs.

Background/Objectives: N-acetyl-galactosamine small interfering RNAs (GalNAc-siRNA) are an emerging class of drugs due to their durable knockdown of disease-related proteins. Direct conjugation of GalNAc onto the siRNA enables targeted uptake into hepatocytes via GalNAc recognition of the Asialoglycoprotein Receptor (ASGPR). With a transient plasma exposure combined with a prolonged liver half-life, GalNAc-siRNA exhibits distinct disposition characteristics. We aimed to develop a generic GalNAc-siRNAs whole-body physiologically based pharmacokinetic-pharmacodynamic (WB-PBPK-PD) model for describing the pharmacokinetic-pharmacodynamic (PK-PD) relationship and overall tissue distribution in the open-source platform Open Systems Pharmacology Suite. Methods: Model development was performed using published studies in mice leveraging the PK-Sim® standard implementation for large molecules with added implementations of ASGPR-mediated liver disposition and downstream target effects. Adequate model performance was achieved across study measurements and included studies adopting a combination of global and compound-specific parameters. Results: The analysis identified significant compound dependencies, e.g., endosomal stability, with direct consequences for the pharmacological effect. Additionally, knowledge gaps in mechanistic understanding related to extravasation and overall tissue distribution were identified during model development. The presented study provides a generic WB-PBPK-PD model for the investigation of GalNAc-siRNAs implemented in a standardized open-source platform.

Hepatocyte targeting via the asialoglycoprotein receptor.

This review highlights the potential of asialoglycoprotein receptor (ASGPR)-mediated targeting in advancing liver-specific treatments and underscores the ongoing progress in the field. First, we provide a comprehensive examination of the nature of ASGPR ligands, both natural and synthetic. Next, we explore various drug delivery strategies leveraging ASGPR, with a particular emphasis on the delivery of therapeutic nucleic acids such as small interfering RNAs (siRNAs) and antisense oligonucleotides (ASOs). An in-depth analysis of the current status of RNA interference (RNAi) and ASO-based therapeutics is included, detailing approved therapies and those in various stages of clinical development (phases 1 to 3). Afterwards, we give an overview of other ASGPR-targeted conjugates, such as those with peptide nucleic acids or aptamers. Finally, targeted protein degradation of extracellular proteins through ASGPR is briefly discussed.

A glycosylated AIE-active Fe(III) photosensitizer activated by the tumor microenvironment for synergistic type I photodynamic and chemodynamic therapy.

Photodynamic therapy (PDT) and chemodynamic therapy (CDT) are both promising cancer treatments to inhibit tumor cells by generating highly cytotoxic reactive oxygen species (ROS). Herein, we report a novel tumor microenvironment (TME) stimulus-responsive water-soluble glycosylated photosensitizer (BT-TPE@Fe-Lac), which can serve as a high-efficiency antitumor agent by combining PDT and CDT, based on the coordination of Fe3+ with lactosyl bis(2-pyridylmethyl)amine and an AIE luminogen (benzothiazole-hydroxytetraphenylethene, BT-TPE). BT-TPE@Fe-Lac is stable under physiological conditions and selectively targets HepG2 cells via asialoglycoprotein receptor (ASGPR)-mediated endocytosis. It rapidly dissociates into AIE-active BT-TPE molecules and a lactosyl ferric(III) complex in the acidic lysosomes of cancer cells. Upon exposure to light, BT-TPE produces O2˙- radicals for type I PDT. The ferric(III) complex is reduced to an Fe(II) complex upon depletion of glutathione, which primes the breakdown of endogenous H2O2 within the tumor microenvironment, thus generating highly toxic ˙OH for enhanced CDT. Compared with the monotherapy of PDT or CDT, BT-TPE@Fe-Lac can significantly increase the intracellular ROS levels to induce more tumor cell death under low drug doses and hypoxia-dependent conditions. This strategy leverages the unique properties of the TME to optimize therapeutic outcomes, offering a promising approach for the TME-responsive nanoplatform in advanced cancer therapy.

Integrated SegFlow, µSIA, and UPLC for Online Sialic Acid Quantitation of Glycoproteins Directly from Bioreactors.

This study emphasizes the critical importance of closely monitoring and controlling the sialic acid content in therapeutic glycoproteins, including EPO, interferon-γ, Orencia, Enbrel, and others, as the level of sialylation directly impacts their pharmacokinetics (PK), immunogenicity, potency, and overall clinical performance due to its influence on protein clearance via hepatic asialoglycoprotein receptors (ASGPR). The ASGPR recognizes and binds to glycoproteins exposed to terminal galactose or N-acetylgalactosamine residues, leading to receptor-mediated endocytosis. Recent studies have demonstrated that sialylation of O-linked glycan plays a role in protecting against macrophage galactose lectin (MGL)-mediated clearance. In addition to the impact on serum half-life, sialylation can influence other clinical outcomes, including immunogenicity, potency, and cytotoxicity. Therefore, the level of sialic acid is a critical quality attribute (CQA), and monitoring and regulating sialylation has become a regulatory requirement to ensure desired clinical performance. To achieve consistent levels of sialic acid-to-protein ratio, the time of upstream harvest and conductivity of downstream wash buffers must be tightly regulated based on the sialic acid content. Therefore, the utilization of process analytical technology (PAT) tools for generating real-time or near-real-time sialic acid content is a business-critical requirement. This work demonstrates the utility of an integrated PAT system for near real-time online sialic acid measurements. The system consists of a micro-sequential injection analyzer (µSIA) interfaced with SegFlow and an ultra performance liquid chromatography (UPLC). The fully automated architecture exemplifies the execution of online sampling, automatic sample preparation, and subsequent online UPLC analysis. This carefully orchestrated PAT framework effectively supports the requirements of QbD-driven continuous bioprocessing.

Targeted nanoparticle delivery unleashes synergistic photothermal and immunotherapeutic effects against hepatocellular carcinoma

The substantial mortality and morbidity of hepatocellular carcinoma, representing 90% of liver cancers, poses a significant health burden. The effectiveness of traditional hepatocellular carcinoma treatments such as surgical resection, radiotherapy, and chemotherapy is limited, underscoring the need for innovative therapeutic strategies. To this end, we synthesized phthalyl-pullulan nanoparticles encapsulating IR780 (an NIR-responsive heptamethine cyanine dye) and R848 (resiquimod; a TLR7/8 agonist) (PIR NPs). Characterization confirmed the size and loading capacity of PIR NPs, and controlled release of R848 therefrom upon NIR irradiation, thereby establishing the potential of this versatile therapeutic tool. PIR NPs were readily taken up by Hepa 1–6 cells in vitro by targeting asialoglycoprotein receptors present on its cellular surface. In in vivo experiments combining photothermal therapy and immunotherapy, following the local near-infrared irradiation, the PIR NPs accumulated in tumor sites induced immunogenic cell death and activated a tumor-specific T-cell immune response, thus highlighting their potent antitumor efficacy. The combined efficacy of photothermal therapy and immunotherapy presents a promising avenue for addressing the shortcomings of traditional hepatocellular carcinoma interventions. This study contributes valuable insights into the development of more effective and targeted therapeutic approaches for hepatocellular carcinoma treatment.Graphical abstract

The low-density lipoprotein receptor: Emerging post-transcriptional regulatory mechanisms.

Cholesterol is a vital component of cellular membranes and is an essential molecule in mammalian physiology. Yet dysregulation of hepatic cholesterol metabolism and an increase in plasma cholesterol is linked to development of atherosclerotic cardiovascular disease. Maintaining tight regulation of cholesterol homeostasis is therefore essential, elegantly highlighted by the control of hepatic low-density lipoprotein receptor (LDLR) abundance and associated lipoprotein clearance. The LDLR was discovered in the 1970's in the seminal work of Brown and Goldstein. This was followed by the development of statins, which promote hepatic clearance of LDL via the LDLR pathway. The discovery two decades ago of Proprotein Convertase Subtilisin-Kexin Type 9 (PCSK9), a secreted protein that binds to the LDLR ectodomain and promotes its degradation, and the clinical development of PCSK9 inhibitors has ushered an effort to uncover additional mechanisms that govern the function and abundance of the LDLR. In recent years this has led to the identification of novel post-transcriptional and post-translational mechanisms that govern the LDLR. This review focuses on these emerging regulatory mechanisms and specifically discusses: (1) Regulation of the LDLR mRNA by RNA-binding proteins and microRNAs, (2) Ubiquitin-dependent degradation of the LDLR protein by the E3 ubiquitin ligases inducible degrader of the LDLR (IDOL) and GOLIATH (RNF130), (3) Control of the LDLR pathway by the asialoglycoprotein receptor 1 (ASGR1), and (4) The role of LDLR ectodomain shedding mediated by membrane-type 1 matrix metalloprotease (MT1-MMP), Bone morphogenetic protein 1 (BMP1), and γ-secretase. Understanding the contribution of these emerging mechanisms to regulation of the LDLR is important for the development of novel LDLR-focused lipid-lowering strategies.

ASGR1 Deficiency Inhibits Atherosclerosis in Western Diet-Fed ApoE-/- Mice by Regulating Lipoprotein Metabolism and Promoting Cholesterol Efflux.

Atherosclerosis is the most common cause of cardiovascular diseases. Clinical studies indicate that loss-of-function ASGR1 (asialoglycoprotein receptor 1) is significantly associated with lower plasma cholesterol levels and reduces cardiovascular disease risk. However, the effect of ASGR1 on atherosclerosis remains incompletely understood; whether inhibition of ASGR1 causes liver injury remains controversial. Here, we comprehensively investigated the effects and the underlying molecular mechanisms of ASGR1 deficiency and overexpression on atherosclerosis and liver injury in mice. We engineered Asgr1 knockout mice (Asgr1-/-), Asgr1 and ApoE double-knockout mice (Asgr1-/-ApoE-/-), and ASGR1-overexpressing mice on an ApoE-/- background and then fed them different diets to assess the role of ASGR1 in atherosclerosis and liver injury. After being fed a Western diet for 12 weeks, Asgr1-/-ApoE-/- mice exhibited significantly decreased atherosclerotic lesion areas in the aorta and aortic root sections, reduced plasma VLDL (very-low-density lipoprotein) cholesterol and LDL (low-density lipoprotein) cholesterol levels, decreased VLDL production, and increased fecal cholesterol contents. Conversely, ASGR1 overexpression in ApoE-/- mice increased atherosclerotic lesions in the aorta and aortic root sections, augmented plasma VLDL cholesterol and LDL cholesterol levels and VLDL production, and decreased fecal cholesterol contents. Mechanistically, ASGR1 deficiency reduced VLDL production by inhibiting the expression of MTTP (microsomal triglyceride transfer protein) and ANGPTL3 (angiopoietin-like protein 3)/ANGPTL8 (angiopoietin-like protein 8) but increasing LPL (lipoprotein lipase) activity, increased LDL uptake by increasing LDLR (LDL receptor) expression, and promoted cholesterol efflux through increasing expression of LXRα (liver X receptor-α), ABCA1 (ATP-binding cassette subfamily A member 1), ABCG5 (ATP-binding cassette subfamily G member 5), and CYP7A1 (cytochrome P450 family 7 subfamily A member 1). These underlying alterations were confirmed in ASGR1-overexpressing ApoE-/- mice. In addition, ASGR1 deficiency exacerbates liver injury in Western diet-induced Asgr1-/-ApoE-/- mice and high-fat diet-induced but not normal laboratory diet-induced and high-fat and high-cholesterol diet-induced Asgr1-/- mice, while its overexpression mitigates liver injury in Western diet-induced ASGR1-overexpressing ApoE-/- mice. Inhibition of ASGR1 inhibits atherosclerosis in Western diet-fed ApoE-/- mice, suggesting that inhibiting ASGR1 may serve as a novel therapeutic strategy to treat atherosclerosis and cardiovascular diseases.

ASGR1 deficiency improves atherosclerosis but alters liver metabolism in ApoE-/- mice

The asialoglycoprotein receptor 1 (ASGR1), a multivalent carbohydrate-binding receptor that primarily is responsible for recognizing and eliminating circulating glycoproteins with exposed galactose (Gal) or N-acetylgalactosamine (GalNAc) as terminal glycan residues, has been implicated in modulating the lipid metabolism and reducing cardiovascular disease burden. In this study, we investigated the impact of ASGR1 deficiency (ASGR1−/−) on atherosclerosis by evaluating its effects on plaque formation, lipid metabolism, circulating immunoinflammatory response, and circulating N-glycome under the hypercholesterolemic condition in ApoE-deficient mice. After 16 weeks of a western-type diet, ApoE−/−/ASGR1−/− mice presented lower plasma cholesterol and triglyceride levels compared to ApoE−/−. This was associated with reduced atherosclerotic plaque area and necrotic core formation. Interestingly, ApoE−/−/ASGR1−/− mice showed increased levels of circulating immune cells, increased AST/ALT ratio, and no changes in the N-glycome profile and liver morphology. The liver of ApoE−/−/ASGR1−/− mice, however, presented alterations in the metabolism of lipids, xenobiotics, and bile secretion, indicating broader alterations in liver homeostasis beyond lipids. These data suggest that improvements in circulating lipid metabolism and atherosclerosis in ASGR1 deficiency is paralleled by a deterioration of liver injury. These findings point to the need for additional evaluation before considering ASGR1 as a pharmacological target for dyslipidemia and cardiovascular disorders.Graphical abstract

Digital Quantitative Detection for Heterogeneous Protein and mRNA Expression Patterns in Circulating Tumor Cells.

Hepatocellular carcinoma (HCC) circulating tumor cells (CTCs) exhibit significant phenotypic heterogeneity and diverse gene expression profiles due to epithelial-mesenchymal transition (EMT). However, current detection methods lack the capacity for simultaneous quantification of multidimensional biomarkers, impeding a comprehensive understanding of tumor biology and dynamic changes. Here, the CTC Digital Simultaneous Cross-dimensional Output and Unified Tracking (d-SCOUT) technology is introduced, which enables simultaneous quantification and detailed interpretation of HCC transcriptional and phenotypic biomarkers. Based on self-developed multi-real-time digital PCR (MRT-dPCR) and algorithms, d-SCOUT allows for the unified quantification of Asialoglycoprotein Receptor (ASGPR), Glypican-3 (GPC-3), and Epithelial Cell Adhesion Molecule (EpCAM) proteins, as well as Programmed Death Ligand 1 (PD-L1), GPC-3, and EpCAM mRNA in HCC CTCs, with good sensitivity (LOD of 3.2 CTCs per mL of blood) and reproducibility (mean %CV = 1.80-6.05%). In a study of 99 clinical samples, molecular signatures derived from HCC CTCs demonstrated strong diagnostic potential (AUC = 0.950, sensitivity = 90.6%, specificity = 87.5%). Importantly, by integrating machine learning, d-SCOUT allows clustering of CTC characteristics at the mRNA and protein levels, mapping normalized heterogeneous 2D molecular profiles to assess HCC metastatic risk. Dynamic digital tracking of eight HCC patients undergoing different treatments visually illustrated the therapeutic effects, validating this technology's capability to quantify the treatment efficacy. CTC d-SCOUT enhances understanding of tumor biology and HCC management.

Abstract 4135023: Effect of mild hepatic impairment on the pharmacokinetics of pelacarsen

Introduction: Pelacarsen, a hepatocyte-directed, N-acetyl galactosamine (GalNAc 3 )–conjugated antisense oligonucleotide, reduces plasma lipoprotein(a) levels by inhibiting apolipoprotein(a) translation. Pelacarsen uptake is mediated by GalNAc 3 binding to the hepatocyte-specific asialoglycoprotein receptor. Hypothesis: It is unknown whether hepatic impairment (HI) impacts pelacarsen uptake and systemic exposure. Aim: This single-dose, open-label, parallel-group, Phase 1 study (NCT05026996) assessed the pharmacokinetics (PK), safety, and tolerability of a single 80 mg subcutaneous dose of pelacarsen in participants with mild HI compared to healthy controls (normal hepatic function). Methods: Eight adults with prior liver cirrhosis and mild HI (Child-Pugh Class A) were matched for sex, age, and body weight with nine healthy controls. PK parameters (C max , AUC 0-72, AUC last , and AUC inf ) were determined using non-compartmental methods. Log-transformed PK parameters were analyzed using a statistical model with group and matching covariates as fixed effects. Least-square geometric means for each group and geometric mean ratios between participants with mild HI and healthy controls were extracted. Safety was also assessed. Results: Pelacarsen C max , AUC last, and AUC inf were, on average, 7%, 37%, and 50% higher, respectively, in participants with mild HI versus matched controls. All 90% confidence intervals around the HI versus healthy control geometric mean ratios included 1 ( Table ). The ranges of all PK parameters and estimated half-lives were similar between groups. In participants with mild HI, pelacarsen exposure approached the same level as controls after eight hours post-dose ( Figure ). No serious adverse events occurred. Conclusion(s): In participants with mild HI, pelacarsen was well tolerated. Mild HI had no significant effect on pelacarsen C max . The non-statistically significant transient increase in AUC was within the exposure range tested in the first-in-human study.

Lipid Nanoparticle-Mediated Liver-Specific Gene Therapy for Hemophilia B.

Background/Objectives: Hemophilia B is a hereditary bleeding disorder due to the production of liver malfunctional factor IX (FIX). Gene therapy with viral vectors offers a cure. However, applications are limited due to pre-existing antibodies, eligibility for children under 12 years of age, hepatotoxicity, and excessive costs. Lipid nanoparticles are a potential alternative owing to their biocompatibility, scalability, and non-immunogenicity. However, their therapeutic applications are still elusive due to the poor transfection efficiencies in delivering plasmid DNA into primary cells and target organs in vivo. To develop efficient liver-targeted lipid nanoparticles, we explored galactosylated lipids to target asialoglycoprotein receptors (ASGPRs) abundantly expressed on hepatocytes. Methods: We developed 12 novel liposomal formulations varying the galactose lipid Gal-LNC 5, cationic lipid MeOH16, DOPE, and cholesterol. We evaluated their physicochemical properties, toxicity profiles, and transfection efficiencies in hepatic cell lines. Among the formulations, Gal-LNC 5 could efficiently transfect the reporter plasmid eGFP in hepatic cell lines and specifically distribute into the liver in vivo. Toward developing functional factor IX, we cloned Padua mutant FIX-L in a CpG-free backbone to enhance the expression and duration. Results: We demonstrated superior expression of FIX with our galactosylated lipid nanoparticle system. Conclusions: The current research presents a specialized lipid nanoparticle system viz. Gal-LNC which is a specialized lipid nanoparticle system for liver-targeted gene therapy in hemophilia B patients that has potential for clinical use. The Gal-LNC successfully delivers a CpG-free Padua FIX gene to liver cells, producing therapeutically relevant levels of FIX protein. Among its benefits are the ideal qualities of stability, targeting the liver specifically, and maximizing efficiency of transfection. Optimization of liver-targeting lipid nanoparticle systems and function FIX plasmids will pave the way for novel lipid nanoparticle-based gene therapy products for hemophilia B and other monogenic liver disorders.

Engineering an Ultrasound-Responsive Glycopolymersome for Hepatocyte-Specific Gene Delivery.

The ability to design liver-targeted gene delivery vectors is plagued with difficulties ranging from carrier-mediated cellular toxicity to challenges in encapsulating sensitive nucleic acids. Herein, we present an ultrasound-responsive glycopolymersome strategy for in situ loading of nucleic acids and achieving hepatocyte-specific gene delivery. This glycopolymersome is self-assembled from a block copolymer, N-acetylgalactosamine-grafted poly(glutamic acid)-block-poly(ε-caprolactone) (PGAGalNAc-b-PCL). GalNAc is introduced to afford liver targeting through the selective binding to the asialoglycoprotein receptor overexpressed on hepatocytes. External ultrasound is utilized to assist in encapsulating nucleic acids within the hydrophilic lumen of glycopolymersomes by exploiting their ultrasound responsiveness nature. Biological studies confirmed the successful encapsulation of plasmid DNA (pDNA) and small interfering RNA (siRNA), rapid nuclear internalization, and efficient gene transfection. These findings collectively demonstrated that this ultrasound-responsive glycopolymersome could be exploited as a novel safe and efficient gene vector targeting hepatocytes.

Identification and Analysis of Phenolic Compounds in Vaccinium uliginosum L. and Its Lipid-Lowering Activity In Vitro.

Vaccinium uliginosum L. (VU), rich in polyphenols, is an important wild berry resource primarily distributed in extremely cold regions. However, the detailed composition of Vaccinium uliginosum L. polyphenols (VUPs) has not been reported, which limits the development and utilization of VU. In this study, VU-free polyphenols (VUFPs) and VU-bound polyphenols (VUBPs) were, respectively, extracted using an ultrasonic, complex enzyme and alkali extraction method; the compositions were identified using ultra-performance liquid chromatography-electrospray ionization mass spectrometry, and lipid-lowering activity in vitro was evaluated. The results showed that 885 polyphenols and 47 anthocyanins were detected in the VUFPs and VUBPs, and 30 anthocyanin monomers were firstly detected in VU. Compared with the model group, the accumulation of lipid droplets and the total cholesterol and triglyceride contents in the high-concentration VUP group reduced by 36.95%, 65.82%, and 62.43%, respectively, and liver damage was also alleviated. It was also found that VUP can regulate the level of Asialoglycoprotein receptor 1, a new target for lipid lowering. In summary, this study provides a detailed report on VUP for the first time, confirming that VUP has lipid-lowering potential in vitro. These findings suggest new strategies and theoretical support for the development and utilization of VU, especially in the field of functional foods.

Deletion of the asialyloglycoprotein receptor-1 (ASGR1) causes atheroprotective effects in vitro and in vivo

Abstract Introduction The asialoglycoprotein receptor 1 (ASGR1) is a hepatic receptor that clears desialylated glycoproteins from the circulation. A loss-of-function mutation in ASGR1 was reported to associate with a 34% reduction in coronary artery disease (CAD) risk, suggesting a role for ASGR1 in CAD. Aim To determine the role of ASGR1 in atherosclerosis and whether deletion of ASGR1 elicits atheroprotective effects. Methods Western blotting, mass spectrometry and flow cytometry assessed ASGR1 expression in cultured macrophages or immune cells collected from the blood and aortas of wildtype mice. Bone marrow-derived macrophages (BMDMs) from wildtype and Asgr1-/- mice were subjected to cholesterol efflux and oxidised low-density lipoprotein (oxLDL) uptake in vitro functionalassays. ELISA and qPCR measured changes in lipid regulators in BMDMs. Asgr1-/- mice were crossed with atherosclerosis-prone apolipoprotein (Apo)e-/- mice (Apoe-/-Asgr1-/-). Stable plaque area was assessed histologically in the aortic sinuses of mice fed a high-cholesterol diet for 8 weeks (n=16/group). Using the tandem stenosis surgical model, unstable plaque was assessed in carotid arteries (n=10/group). Human ASGR1 was measured by ELISA in peripheral blood mononuclear cells (PBMCs) isolated from patient samples (n=18). Results Western blotting and mass spectrometry discovered ASGR1 is expressed in macrophages. Immunofluorescence identified the presence of ASGR1 in aortic sinus plaque. Flow cytometry revealed ASGR1 is expressed in both inflammatory and patrolling monocytes, neutrophils, macrophages and dendritic cells of blood and aortas. Asgr1-/- BMDMs elicited greater cholesterol efflux (+39%, P<0.05) and decreased oxLDL uptake (-15%, P<0.05), compared to wildtype BMDMs. Moreover, Asgr1-/- BMDMs had significantly higher LDL receptor protein levels (+2-fold), and Lxra (+2-fold) and Pparg (+1.5-fold) mRNA levels than wildtype BMDMs, P<0.001. Plasma from Asgr1-/- mice had lower total (-25%, P<0.05) and LDL (-36%, P<0.05) cholesterol concentrations than wildtype mice. Apoe-/-Asgr1-/- mice developed less stable plaque in aortic sinuses (-37%, P<0.001) than Apoe-/- controls, as well as smaller unstable plaques in carotid arteries (-49%, P<0.05). Finally, in a human population, ASGR1 protein levels were higher in PBMCs from patients with coronary plaque (+61%, P<0.05), than those without plaque, determined from coronary angiograms. Conclusion ASGR1 is expressed on monocytes, macrophages and in plaques, and human PBMC ASGR1 associates with coronary plaque. Deletion of ASGR1 causes atheroprotective functions in macrophages in vitro and reduced plaque burden in vivo. Our findings demonstrate ASGR1 is important in atherosclerosis with implications for ASGR1 as a therapeutic target.

68Ga-Labeled TRAP-Based Glycoside Trimers for Imaging of the Functional Liver Reserve.

The exclusive asialoglycoprotein receptor (ASGR) expression on hepatocytes makes it an attractive target for imaging of the functional liver reserve. Here, we present a set of TRAP-based glycoside trimers and evaluate their imaging properties compared to the gold standard [99mTc]Tc-GSA. The click-chemistry-based synthesis approach provided easy access to trimeric low-molecular-weight compounds. Labeling with 68Ga was carried out in high radiochemical yields (>99%). Complexes showed high stability and hydrophilicity. Protein binding ranged between 10 and 25%. Highest binding affinity (IC50) and best liver accumulation were found for [68Ga]Ga-T3N3, followed by [68Ga]Ga-T3G3 and [68Ga]Ga-T0G3. Rapid elimination from the rest of the body resulted in excellent target-to-background ratios. Our studies confirmed that high ASGR uptake depends on the correct spacer design and that N-acetylgalactosamine improves targeting properties in vivo. Thus, [68Ga]Ga-T3N3 represents a new low-molecular-weight radiopharmaceutical with pharmacokinetics similar to those of [99mTc]Tc-GSA.

Novel NTCP ligand dimeric bile acid conjugated with ASO reduce hepatitis B virus surface antigen in vivo

Hepatitis B virus (HBV) specifically infects hepatocytes and causes severe liver diseases. However, functional cure is rarely attainable by current treatment modalities. Anti-sense oligonucleotide (ASO), which targets pregenomic RNAs to reduce hepatitis B virus (HBV) antigen production and viral replication, has been studied as a novel treatment strategy for HBV cure and can be conjugated with N-acetylgalactosamine (GalNAc), thereby enhancing hepatocyte uptake via the asialoglycoprotein receptor (ASGPR). In comparison to GalNAc-ASO conjugation, clinical research indicates that unconjugated ASO is more effective in reducing hepatitis B virus surface antigen level. Recent studies have revealed that human sodium taurocholate co-transporting polypeptide (NTCP) is a functional cellular receptor for hepatitis B virus (HBV), and the bivalent bile acid structure may interact with multiple binding sites on NTCP, yielding much stronger interaction and substantially improved binding affinity. In this study, we synthesized NTCP ligand-antisense oligonucleotide (ASO) conjugation and evaluated the potential of antiviral therapy specifically reduction of HBV antigenemia in mice in vivo.