Immunomodulatory Therapy of Inflammatory Liver Disease Using Selectin-Binding Glycopolymers

Nanotherapeutics for Alleviating Anesthesia-Associated Complications

Current management of anesthesia-associated complications falls short in terms of both efficacy and safety. Nanomaterials with versatile properties and unique nano-bio interactions hold substantial promise as therapeutics for addressing these complications. This review conducts a thorough examination of the existing nanotherapeutics and highlights the strategies for developing prospective nanomedicines to mitigate anesthetics-related toxicity. Initially, general, regional, and local anesthesia along with the commonly used anesthetics and related prevalent side effects are introduced. Furthermore, employing nanotechnology to prevent and alleviate the complications of anesthetics is systematically demonstrated from three aspects, that is, developing 1) safe nano-formulization for anesthetics; 2) nano-antidotes to sequester overdosed anesthetics and alter their pharmacokinetics; 3) nanomedicines with pharmacodynamic activities to treat anesthetics toxicity. Finally, the prospects and challenges facing the clinical translation of nanotherapeutics for anesthesia-related complications are discussed. This work provides a comprehensive roadmap for developing effective nanotherapeutics to prevent and mitigate anesthesia-associated toxicity, which can potentially revolutionize the management of anesthesia complications.

Nanoparticular Carriers As Objects to Study Intentional and Unintentional Bioconjugation

Synthetic nanoparticles are interesting to use in the study of ligation with natural biorelevant structures. That is because they present an intermediate situation between reactions onto soluble polymers or onto solid surfaces. In addition, differently functionalized nanoparticles can be separated and studied independently thereafter. So what would be a "patchy functionalization" on a macroscopic surface results in differently functionalized nanoparticles, which can be separated after the interaction with body fluids. This paper will review bioconjugation of such nanoparticles with a special focus on recent results concerning the formation of a protein corona by unspecific adsorption (lower lines of TOC), which presents an unintentional bioconjugation, and on new aspects of intentionally performed bioconjugation by covalent chemistry (upper line). For this purpose, it is important that polymeric nanoparticles without a protein corona can be prepared. This opens, e.g., the possibility to look for special proteins adsorbed as a result of the natural compound ligated to the nanoparticle by covalent chemistry, like the Fc part of antibodies. At the same time, the use of highly reactive, bioorthogonal functional groups (inverse electron demand Diels-Alder cycloaddition) on the nanoparticles allows an efficient ligation after administration inside the body, i.e., in vivo.

Combined Amphiphilic Silybin Meglumine Nanosuspension Effective Against Hepatic Fibrosis in Mice Model

Introduction

Silybin (SLB) as an effective hepatoprotective phytomedicine has been limited by its hydrophobicity, poor bioavailability and accumulation at lesion sites. Additionally, present drug loading methods are impeded by their low drug loading capacity, potential hazard of materials and poor therapeutic effects. Consequently, there is a pressing need to devise an innovative approach for preparing nanosuspensions loaded with both SLB and Silybin Meglumine salt (SLB-M), as well as to investigate the therapeutic effects of SLB nanosuspensions against hepatic fibrosis.

Methods

The SLB nanosuspension (NS-SLB) was prepared and further modified with a hyaluronic acid-cholesterol conjugate (NS-SLB-HC) to improve the CD44 targeting proficiency of NS-SLB. To validate the accumulation of CD44 and ensure minimal cytotoxicity, cellular uptake and cytotoxicity assessments were carried out for the nanosuspensions. Western blotting was employed to evaluate the anti-hepatic fibrosis efficacy in LX-2 cells by inhibiting the secretion of collagen I. Hepatic fibrosis mouse models were used to further confirm the effectiveness of NS-SLB and NS-SLB-HC against hepatic fibrosis in vivo.

Results

Uniform nanosuspensions were prepared through self-assembly, achieving high drug loading rates of 89.44% and 60.67%, respectively. Both SLB nanosuspensions showed minimal cytotoxicity in cellular environments and mitigated hepatic fibrosis in vitro. NS-SLB-HC was demonstrated to target activated hepatic stellate cells by receptor-ligand interaction between HA and CD44. They can reverse hepatic fibrosis in vivo by downregulating TGF-β and inhibiting the secretion of α-SMA and collagen I.

Conclusion

Designed as a medical excipient analogue, SLB-M was aimed to establish an innovative nanosuspension preparation method, characterized by high drug loading capacity and a notable impact against hepatic fibrosis.

Multivalent glycosystems for human lectins

Human lectins are involved in a wide variety of biological processes, both physiological and pathological, which have attracted the interest of the scientific community working in the glycoscience field. Multivalent glycosystems have been employed as useful tools to understand carbohydrate-lectin binding processes as well as for biomedical applications. The review shows the different scaffolds designed for a multivalent presentation of sugars and their corresponding binding studies to lectins and in some cases, their biological activities. We summarise this research by organizing based on lectin types to highlight the progression in this active field. The paper provides an overall picture of how these contributions have furnished relevant information on this topic to help in understanding and participate in these carbohydrate-lectin interactions.

Targeting Ligand Independent Tropism of siRNA-LNP by Small Molecules for Directed Therapy of Liver or Myeloid Immune Cells

Hepatic clearance of lipid nanoparticles (LNP) with encapsulated nucleic acids restricts their therapeutic applicability. Therefore, tools for regulating hepatic clearance are of high interest for nucleic acid delivery. To this end, this work employs wild-type (WT) and low-density lipoprotein receptor (Ldlr)-/- mice pretreated with either a leukotriene B4 receptor inhibitor (BLT1i) or a high-density lipoprotein receptor inhibitor (HDLRi) prior to the injection of siRNA-LNP. This work is able to demonstrate significantly increased hepatic uptake of siRNA-LNP by the BLT1i in Ldlr-/- mice by in vivo imaging and discover an induction of specific uptake-related proteins. Irrespective of the inhibitors and Ldlr deficiency, the siRNA-LNP induced RNA-binding and transport-related proteins in liver, including haptoglobin (HP) that is also identified as most upregulated serum protein. This work observes a downregulation of proteins functioning in hepatic detoxification and of serum opsonins. Most strikingly, the HDLRi reduces hepatic uptake and increases siRNA accumulation in spleen and myeloid immune cells of blood and liver. RNA sequencing demonstrates leukocyte recruitment by the siRNA-LNP and the HDLRi through induction of chemokine ligands in liver tissue. The data provide insights into key mechanisms of siRNA-LNP biodistribution and indicate that the HDLRi has potential for extrahepatic and leukocyte targeting.

zVAD alleviates experimental autoimmune hepatitis in mice by increasing the sensitivity of macrophage to TNFR1-dependent necroptosis

BACKGROUND & AIMS

Autoimmune hepatitis (AIH) is characterized by hepatocyte destruction, leading to lymphocyte and macrophage accumulation in the liver. Macrophages are key drivers of AIH. A membrane-permeable pan-caspase inhibitor, Z-Val-Ala-DL-Asp-fluoromethylketone (zVAD), induces macrophage necroptosis in response to certain stimuli. However, the function of zVAD in the pathogenesis of autoimmune hepatitis remains elusive. In this study, we aimed to evaluate the effect and explore the underlying mechanisms of zVAD against AIH.

METHODS

Murine acute autoimmune liver injury was established by concanavalin A (ConA) injection. Bone marrow-derived macrophages (BMDMs) were used in adoptive cell transfer experiments. The mechanism of action of zVAD was examined using macrophage cell lines and BMDMs. Phosphorylation of mixed lineage kinase domain-like proteins was used as a marker of necroptosis.

RESULTS

Treatment with zVAD increased necroptosis, reduced inflammatory cytokine production, and alleviated liver injury in a ConA-induced liver injury mouse model. Regardless of zVAD treatment, macrophage deletion resulted in reduced neutrophil accumulation and relieved ConA-induced liver injury. In vitro studies have shown that zVAD pretreatment promotes lipopolysaccharide-induced macrophage necroptosis and leads to reduced pro-inflammatory cytokine and chemokine secretion. Transferring zVAD-pretreated BMDMs in mice notably reduced ConA-associated liver inflammation and injury, resulting in lower mortality than that observed after transferring normal BMDMs. Mechanistically, zVAD treatment increased the expression of tumour necrosis factor receptor (TNFR)-1 and interleukin (IL)-10 in macrophages. TNFR1 expression decreased upon transfection with IL-10-specific small interfering RNAs and blocking of TNFR1 decreased macrophage necroptosis.

CONCLUSIONS

We found that zVAD alleviated ConA-induced liver injury by increasing the sensitivity of macrophages to necroptosis via IL-10-induced TNFR1 expression. This study provides new insights into the treatment of autoimmune hepatitis via zVAD-induced macrophage necroptosis.

Tollip Orchestrates Macrophage Polarization to Alleviate Intestinal Mucosal Inflammation

BACKGROUND AND AIMS

Regulation of macrophage polarization is a promising strategy for treating inflammatory bowel disease [IBD]. Tollip is an important negative regulator of Toll-like receptor [TLR]-mediated innate immunity with downregulated expression in the colon tissues of patients with IBD. This study aimed to regulate the expression of Tollip to affect macrophage polarization.

METHODS

A molecular, targeted immunotherapy method was developed by linking mannose-modified trimethyl chitosan [MTC] with Tollip-expressing plasmids via ionic cross-linking, forming MTC-Tollip nanoparticles with a targeting function. MTC-Tollip selectively targeted mouse intestinal macrophages to regulate the polarization of macrophages for mucosal repair.

RESULTS

Orally administered MTC-Tollip significantly elevated Tollip expression in intestinal tissue. Compared with MTC-negative control [NC]-treated mice in which colitis was induced with dextran sodium sulphate [DSS], the MTC-Tollip nanoparticle-treated mice exhibited decreased body weight loss and colon shortening, lower proinflammatory cytokine expression in colon tissues, and greater mucosal barrier integrity. MTC-Tollip treatment decreased TNF-α and iNOS expression but increased CD206 and Arg-1 expression in colon tissue. Tollip overexpression in mouse peritoneal macrophages inhibited lipopolysaccharide [LPS]-induced proinflammatory cytokine production and promoted IL-4-induced M2 expression. The progression of peritoneal macrophages extracted from Tollip-/- mice confirmed the effect of Tollip on macrophage polarization. Western blots showed that Tollip overexpression attenuated the upregulation of TLR pathway-associated targets in M1 macrophages.

CONCLUSIONS

MTC nanoparticles can be 'intelligent' carriers in immunotherapy. The modulation of Tollip expression in macrophages may be a novel treatment approach for IBD.

A carrier-free metal-organic hybrid nanoassembly with combination anti-viral and hepato-protective activity for hepatitis B treatment

Hepatitis B represents a major global public health burden, which is caused by the hepatitis B virus (HBV) with a high infection rate. Although several anti-HBV drugs have been developed for clinical treatment of hepatitis B, the current therapeutic strategies still suffer from undeniable adverse effects, insufficient efficacy after systemic administration and chronic inflammation. Here, we develop a carrier-free metal-organic hybrid nanoassembly that is co-loaded with tenofovir (TFV), an anti-viral agent and phosphorylated glycyrrhetinic acid (GAP), an anti-inflammatory compound (TFV/GAP/NA) to enhance the anti-HBV effect and alleviate the inflammatory response for hepatitis B treatment. The nanoassembly is easily prepared through the ionic interactions between the anionic phosphonate/phosphate groups from TFV/GAP and the zirconium cation, which has a stable nanostructure and a high drug-loading capacity. The nanoassembly prolongs the circulation time with reduced drug leakage in the blood and elevates drug accumulation in the liver after intravascular administration. After internalization mediated by the GAP ligand-GA receptor interaction, TFV/GAP/NA disassembles by the phosphatase-triggered degradation of the phosphate ester bonds in GAP and releases TFV, GAP and GA within the HBV-positive hepatocytes. The released TFV interferes with the HBV polymerase to inhibit the viral DNA replication, while the released GAP and GA suppress the pro-inflammatory protein expression. In mouse models, treatment with TFV/GAP/NA inhibits HBV production and alleviates inflammation-mediated liver injury.

Endothelial Cell Adhesion Molecules- (un)Attainable Targets for Nanomedicines

Endothelial cell adhesion molecules have long been proposed as promising targets in many pathologies. Despite promising preclinical data, several efforts to develop small molecule inhibitors or monoclonal antibodies (mAbs) against cell adhesion molecules (CAMs) ended in clinical-stage failure. In parallel, many well-validated approaches for targeting CAMs with nanomedicine (NM) were reported over the years. A wide range of potential applications has been demonstrated in various preclinical studies, from drug delivery to the tumor vasculature, imaging of the inflamed endothelium, or blocking immune cells infiltration. However, no NM drug candidate emerged further into clinical development. In this review, we will summarize the most advanced examples of CAM-targeted NMs and juxtapose them with known traditional drugs against CAMs, in an attempt to identify important translational hurdles. Most importantly, we will summarize the proposed strategies to enhance endothelial CAM targeting by NMs, in an attempt to offer a catalog of tools for further development.

Liver Fibrosis-From Mechanisms of Injury to Modulation of Disease

The Transregional Collaborative Research Center "Organ Fibrosis: From Mechanisms of Injury to Modulation of Disease" (referred to as SFB/TRR57) was funded for 13 years (2009-2021) by the German Research Council (DFG). This consortium was hosted by the Medical Schools of the RWTH Aachen University and Bonn University in Germany. The SFB/TRR57 implemented combined basic and clinical research to achieve detailed knowledge in three selected key questions: (i) What are the relevant mechanisms and signal pathways required for initiating organ fibrosis? (ii) Which immunological mechanisms and molecules contribute to organ fibrosis? and (iii) How can organ fibrosis be modulated, e.g., by interventional strategies including imaging and pharmacological approaches? In this review we will summarize the liver-related key findings of this consortium gained within the last 12 years on these three aspects of liver fibrogenesis. We will highlight the role of cell death and cell cycle pathways as well as nutritional and iron-related mechanisms for liver fibrosis initiation. Moreover, we will define and characterize the major immune cell compartments relevant for liver fibrogenesis, and finally point to potential signaling pathways and pharmacological targets that turned out to be suitable to develop novel approaches for improved therapy and diagnosis of liver fibrosis. In summary, this review will provide a comprehensive overview about the knowledge on liver fibrogenesis and its potential therapy gained by the SFB/TRR57 consortium within the last decade. The kidney-related research results obtained by the same consortium are highlighted in an article published back-to-back in Frontiers in Medicine.

Carbohydrate-Based Macromolecular Biomaterials

Carbohydrates are the most abundant and one of the most important biomacromolecules in Nature. Except for energy-related compounds, carbohydrates can be roughly divided into two categories: Carbohydrates as matter and carbohydrates as information. As matter, carbohydrates are abundantly present in the extracellular matrix of animals and cell walls of various plants, bacteria, fungi, etc., serving as scaffolds. Some commonly found polysaccharides are featured as biocompatible materials with controllable rigidity and functionality, forming polymeric biomaterials which are widely used in drug delivery, tissue engineering, etc. As information, carbohydrates are usually referred to the glycans from glycoproteins, glycolipids, and proteoglycans, which bind to proteins or other carbohydrates, thereby meditating the cell-cell and cell-matrix interactions. These glycans could be simplified as synthetic glycopolymers, glycolipids, and glycoproteins, which could be afforded through polymerization, multistep synthesis, or a semisynthetic strategy. The information role of carbohydrates can be demonstrated not only as targeting reagents but also as immune antigens and adjuvants. The latter are also included in this review as they are always in a macromolecular formulation. In this review, we intend to provide a relatively comprehensive summary of carbohydrate-based macromolecular biomaterials since 2010 while emphasizing the fundamental understanding to guide the rational design of biomaterials. Carbohydrate-based macromolecules on the basis of their resources and chemical structures will be discussed, including naturally occurring polysaccharides, naturally derived synthetic polysaccharides, glycopolymers/glycodendrimers, supramolecular glycopolymers, and synthetic glycolipids/glycoproteins. Multiscale structure-function relationships in several major application areas, including delivery systems, tissue engineering, and immunology, will be detailed. We hope this review will provide valuable information for the development of carbohydrate-based macromolecular biomaterials and build a bridge between the carbohydrates as matter and the carbohydrates as information to promote new biomaterial design in the near future.

Lipid nanoparticle formulations for targeting leukocytes with therapeutic RNA in liver fibrosis

Obesity and low-grade inflammation are promoters of a multitude of diseases including liver fibrosis. Activation of the mobile leukocytes has a major impact on the outcome of inflammatory disease and can hence foster or mitigate liver fibrosis. This renders immunological targets valuable for directed interventions using nanomedicines. Particularly, RNA-based drugs formulated as lipid nanoparticles (LNP) can open new avenues for the personalized treatment of liver fibrosis both through specific interference and via the induction of the expression of functional and therapeutic proteins. Using microfluidics technology, all components, including lipid-anchored targeting ligands, are assembled in a single-step mixing process. A highlight is set to immunologically relevant liver cell types that are most vulnerable for being reached by LNP. A selection of LNP from other therapeutic fields applicable for reaching these cells in liver fbrosis is summarized. Furthermore, recent proceedings and major obstacles in the field of these targeted LNP are presented.

Immunomodulatory nanosystems for treating inflammatory diseases

Inflammatory disease (ID) is an umbrella term encompassing all illnesses involving chronic inflammation as the central manifestation of pathogenesis. These include, inflammatory bowel diseases, hepatitis, pulmonary disorders, atherosclerosis, myocardial infarction, pancreatitis, arthritis, periodontitis, psoriasis. The IDs create a severe burden on healthcare and significantly impact the global socio-economic balance. Unfortunately, the standard therapies that rely on a combination of anti-inflammatory and immunosuppressive agents are palliative and provide only short-term relief. In contrast, the emerging concept of immunomodulatory nanosystems (IMNs) has the potential to address the underlying causes and prevent reoccurrence, thereby, creating new opportunities for treating IDs. The IMNs offer exquisite ability to precisely modulate the immune system for a therapeutic advantage. The nano-sized dimension of IMNs allows them to efficiently infiltrate lymphatic drainage, interact with immune cells, and subsequently to undergo rapid endocytosis by hyperactive immune cells (HICs) at inflamed sites. Thus, IMNs serve to restore dysfunctional or HICs and alleviate the inflammation. We identified that different IMNs exert their immunomodulatory action via either of the seven mechanisms to modulate; cytokine production, cytokine neutralization, cellular infiltration, macrophage polarization, HICs growth inhibition, stimulating T-reg mediated tolerance and modulating oxidative-stress. In this article, we discussed representative examples of IMNs by highlighting their rationalization, design principle, and mechanism of action in context of treating various IDs. Lastly, we highlighted technical challenges in the application of IMNs and explored the future direction of research, which could potentially help to overcome those challenges.

Drug-induced liver injury and prospect of cytokine based therapy; A focus on IL-2 based therapies

Drug-induced liver injury (DILI) is one of the most frequent sources of liver failure and the leading cause of liver transplant. Common non-prescription medications such as non-steroidal anti-inflammatory drugs (NSAIDs), acetaminophen, and other prescription drugs when taken at more than the recommended doses may lead to DILI. The severity of DILI is affected by factors such as age, ethnicity, race, gender, nutritional status, on-going liver diseases, renal function, pregnancy, alcohol consumption, and drug-drug interactions. Characteristics of DILI-associated inflammation include apoptosis and necrosis of hepatocytes and hepatic infiltration of pro-inflammatory immune cells. If untreated or if the inflammation continues, DILI and associated hepatic inflammation may lead to development of hepatocarcinoma. The therapeutic approach for DILI-associated hepatic inflammation depends on whether the inflammation is acute or chronic. Discontinuing the causative medication, vaccination, and special dietary supplementation are some of the conventional approaches to treat DILI. In this review, we discuss a concise overview of DILI-associated liver complications, and current therapeutic options with special emphasis on biologics including the scope of cytokine therapy in hepatic repair and resolution of inflammation caused by over- the-counter (OTC) or prescription drugs.

Kupffer cell-targeting strategy for the protection of hepatic ischemia/reperfusion injury

The aim of this study is to evaluate the effect of rare earth upconversion nanoparticles (UCNs) on hepatic ischemia reperfusion injury (IRI) and explore its possible mechanism. Hepatic IRI seriously affects the prognosis of patients undergoing liver surgery. Liver-resident Kupffer cells have been reported to promote IRI. Nanomedicines are known to be effective in the treatment of liver diseases, however, Kupffer cell-targeting nanomedicines for the treatment of IRI are yet to be developed. As potential bioimaging nanomaterials, UCNs have been found to specifically deplete Kupffer cells, but the underlying mechanism is unknown. In this study, we found that UCNs specifically depleted Kupffer cells by pyroptosis, while the co-administration of the caspase-1 inhibitor VX-765 rescued the UCN-induced Kupffer cell pyroptosis in mice. Furthermore, the pre-depletion of Kupffer cells by the UCNs significantly suppressed the release of inflammatory cytokines and effectively improved hepatic IRI. The rescue of the pyroptosis of the Kupffer cells by VX-765 abrogated the protective effect of UCNs on the liver. These results suggest that UCNs are highly promising for the development of Kupffer cell-targeting nanomedicines for intraoperative liver protection.

Multifunctionalized Brush-Like Glycopolymers with High Affinity to P-Selectin and Antitumor Metastasis Activity

Glycopolymers that can mimic natural glycosaminoglycan, such as heparin, have shown great potentials in inhibition of cancer metastasis. In the current work, a novel series of brush-like glycopolymers (BGPs) with simultaneous functionalization of various monosaccharide or disaccharide compositions have been synthesized through a new grafting-polymerization strategy, in order to mimic the activities of both heparin and P-selectin ligand PSGL-1. In the subsequent in vitro assays of antiadhesion, platelets activation, heparanase inhibition, and so on, BGP-SFH, as one of the BGPs with the composition of the combined three sugar units, sialic acids, fucoses, and heparin disaccharides, showed the highest antimetastasis ability, similar to its prototype heparin. Moreover, in a mouse metastatic melanoma model, the BGP-SFH also inhibited B16 cell metastasis effectively. Thus, the current work not only demonstrated a type of promising antimetastasis glycopolymer BGPs, but also illustrated an easy synthetic approach to multifunctionalized glycopolymers, leading to potential applications for broader biomedical research.

Silencing lncRNA TUG1 Alleviates LPS-Induced Mouse Hepatocyte Inflammation by Targeting miR-140/TNF

Hepatitis is a major public health problem that increases the risk of liver cirrhosis and liver cancer. Numerous studies have revealed that long non-coding RNAs (lncRNAs) exert essential function in the inflammatory response of multiple organs. Herein, we aimed to explore the effect of lncRNA TUG1 in LPS-induced hepatocyte inflammation response and further illuminate the underlying mechanisms. Mice were intraperitoneally injected with LPS, and the liver inflammation was evaluated. Microarray showed that lncRNA TUG1 was upregulated in LPS-induced hepatocyte inflammation. qRT-PCR and immunofluorescence assay indicated a significant increase of TUG1 in mice with LPS injection. Functional analysis showed that si-TUG1 inhibited LPS-induced inflammation response in mice liver, inhibited apoptosis level, and protected liver function. Then, we knock down TUG1 in normal human hepatocyte AML12. Consistent with in vivo results, si-TUG1 removed the injury of LPS on AML12 cells. Furthermore, TUG1 acted as a sponge of miR-140, and miR-140 directly targeted TNFα (TNF). MiR-140 or si-TNF remitted the beneficial effects of TUG1 on LPS-induced hepatocyte inflammation response both in vitro and in vivo. Our data revealed that deletion of TUG1 protected against LPS-induced hepatocyte inflammation via regulating miR-140/TNF, which might provide new insight for hepatitis treatment.

Modulation of Leukocytes of the Innate Arm of the Immune System as a Potential Approach to Prevent the Onset and Progression of Type 1 Diabetes

Type 1 diabetes (T1D) is characterized by insulin deficiency resulting from the selective destruction of pancreatic β-cells by self-reactive T cells. Recent evidence demonstrates that innate immune responses substantially contribute to the pathogenesis of T1D, as they represent a first line of response to danger/damage signals. Here we discuss evidence on how, in a relapsing-remitting pattern, pancreas remodeling, diet, microbiota, gut permeability, and viral/bacterial infections induce the accumulation of leukocytes of the innate arm of the immune system throughout the pancreas. The subsequent acquisition and presentation of endocrine and exocrine antigens to the adaptive arm of the immune system results in a chronic progression of pancreatic damage. This process provides for the generation of self-reactive T-cell responses; however, the relative weight that genetic and environmental factors have on the etiopathogenesis of T1D is endotype imprinted and patient specific. With this Perspectives in Diabetes, our goal is to encourage the scientific community to rethink mechanisms underlying T1D pathogenesis and to consider therapeutic approaches that focus on these processes in intervention trials within new-onset disease as well as in efforts seeking the disorder's prevention in individuals at high risk.

Sulfated polysaccharide directs therapeutic angiogenesis via endogenous VEGF secretion of macrophages

Notwithstanding the remarkable progress in the clinical treatment of ischemic disease, proangiogenic drugs mostly suffer from their abnormal angiogenesis and potential cancer risk, and currently, no off-the-shelf biomaterials can efficiently induce angiogenesis. Here, we reported that a semisynthetic sulfated chitosan (SCS) readily engaged anti-inflammatory macrophages and increased its secretion of endogenous vascular endothelial growth factor (VEGF) to induce angiogenesis in ischemia via a VEGF-VEGFR2 signaling pathway. The depletion of host macrophages abrogated VEGF secretion and vascularization in implants, and the inhibition of VEGF or VEGFR2 signaling also disrupted the macrophage-associated angiogenesis. In addition, in a macrophage-inhibited mouse model, SCS efficiently helped to recover the endogenous levels of VEGF and the number of CD31^hiEmcn^hi vessels in ischemia. Thus, both sulfated group and pentasaccharide sequence in SCS played an important role in directing the therapeutic angiogenesis, indicating that this highly bioactive biomaterial can be harnessed to treat ischemic disease.

Say no to drugs: Bioactive macromolecular therapeutics without conventional drugs

The vast majority of nanomedicines (NM) investigated today consists of a macromolecular carrier and a drug payload (conjugated or encapsulated), with a purpose of preferential delivery of the drug to the desired site of action, either through passive accumulation, or by active targeting via ligand-receptor interaction. Several drug delivery systems (DDS) have already been approved for clinical use. However, recent reports are corroborating the notion that NM do not necessarily need to include a drug payload, but can exert biological effects through specific binding/blocking of important target proteins at the site of action. The seminal work of Kopeček et al. on N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers containing biorecognition motifs (peptides or oligonucleotides) for crosslinking cell surface non-internalizing receptors of malignant cells and inducing their apoptosis, without containing any low molecular weight drug, led to the definition of a special group of NM, termed Drug-Free Macromolecular Therapeutics (DFMT). Systems utilizing this approach are typically designed to employ pendant targeting-ligands on the same macromolecule to facilitate multivalent interactions with receptors. The lack of conventional small molecule drugs reduces toxicity and adverse effects at off-target sites. In this review, we describe different types of DFMT that possess biological activity without attached low molecular weight drugs. We classified the relevant research into several groups by their mechanisms of action, and compare the advantages and disadvantages of these different approaches. We show that identification of target sites, specificity of attached targeting ligands, binding affinity and the synthesis of carriers of defined size and ligand spacing are crucial aspects of DFMT development. We further discuss how knowledge in the field of NM accumulated in the past few decades can help in the design of a successful DFMT to speed up the translation into clinical practice.

Regulatory T Cells in Autoimmune Hepatitis: Unveiling Their Roles in Mouse Models and Patients

Autoimmune hepatitis (AIH) is a severe and chronic liver disease, and its incidence has increased worldwide in recent years. Research into the pathogenesis of AIH remains limited largely owing to the lack of suitable mouse models. The concanavalin A (ConA) mouse model is a typical and well-established model used to investigate T cell-dependent liver injury. However, ConA-induced hepatitis is acute and usually disappears after 48 h; thus, it does not mimic the pathogenesis of AIH in the human body. Several studies have explored various AIH mouse models, but as yet there is no widely accepted and valid mouse model for AIH. Immunosuppression is the standard clinical therapy for AIH, but patient side effects and recurrence limit its use. Regulatory T cells (Tregs) play critical roles in the maintenance of immune homeostasis and in the prevention of autoimmune diseases, which may provide a potential therapeutic target for AIH therapy. However, the role of Tregs in AIH has not yet been clarified, partly because of difficulties in diagnosing AIH and in collecting patient samples. In this review, we discuss the studies related to Treg in various AIH mouse models and patients with AIH and provide some novel insights for this research area.

Carbohydrate supramolecular chemistry: beyond the multivalent effect

(Hetero)multivalency acts as a multichannel switch that shapes the supramolecular properties of carbohydrates in an intrinsically multifactorial biological context.

Attenuation of neutrophil-mediated liver injury in mice by drug-free E-selectin binding polymer

Inflammation with neutrophils infiltration is a prominent feature of alcohol-related liver disease (ARLD) and contributes to the severity of liver injury. Although an array of potential treatments has been studied, the standard treatment regimen is controversial and can induce severe side effects and infection-related complications. E-selectin, a cytokine inducible cell adhesion molecule, mediates the initial interaction of leucocytes with endothelial cells, and facilitates their further adhesion and extravasation into inflamed tissues. Given the important role of E-selectin in leukocytes trafficking, we hypothesized that a synthetic polymer presenting multiple copies of E-selectin binding peptide in a polyvalent manner (P-Esbp) may block the "roads" that facilitate neutrophil infiltration, inhibit the recruitment of neutrophils to the inflamed sites and reduce the extent of liver injury. We now demonstrate in vitro that P-Esbp reduced the recruitment of neutrophils (collected from blood of donors) on activated human umbilical vein endothelial cells (HUVEC) under flow conditions. Pre-treatment of mice with P-Esbp prior to alcohol binge attenuated alcohol-induced serum transaminase (ALT, AST) elevation, reduced pro-inflammatory cytokines (TNFα and IL-1ẞ) and chemokines (MIP-2/CXCL2 and MCP-1/CCL2) in National Institute on Alcohol Abuse and Alcoholism (NIAAA) model. Also, the up-regulation of neutrophil marker Ly6G and the number of MPO positive cells in the injured tissue was significantly reduced by the treatment, indicating diminished neutrophil infiltration. Moreover, as a result of P-Esbp treatment, E-selectin expression in the liver (mRNA and protein level) was downregulated, suggesting a potential to decrease ongoing local inflammatory response. Overall, our findings highlight the anti-inflammatory properties of the "drug-free" P-Esbp and its therapeutic potential to attenuate an excessive inflammation where infiltrating neutrophils can damage tissues and organs.

"Tuning aggregative versus non-aggregative lectin binding with glycosylated nanoparticles by the nature of the polymer ligand"

Glycan-lectin interactions drive a diverse range of biological signaling and recognition processes. The display of glycans in multivalent format enables their intrinsically weak binding affinity to lectins to be overcome by the cluster glycoside effect, which results in a non-linear increase in binding affinity. As many lectins have multiple binding sites, upon interaction with glycosylated nanomaterials either aggregation or surface binding without aggregation can occur. Depending on the application area, either one of these responses are desirable (or undesirable) but methods to tune the aggregation state, independently from the overall extent/affinity of binding are currently missing. Herein, we use gold nanoparticles decorated with galactose-terminated polymer ligands, obtained by photo-initiated RAFT polymerization to ensure high end-group fidelity, to show the dramatic impact on agglutination behaviour due to the chemistry of the polymer linker. Poly(N-hydroxyethyl acrylamide) (PHEA)-coated gold nanoparticles, a polymer widely used as a non-ionic stabilizer, showed preference for aggregation with lectins compared to poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA)-coated nanoparticles which retained colloidal stability, across a wide range of polymer lengths and particle core sizes. Using biolayer interferometry, it was observed that both coatings gave rise to similar binding affinity and hence provided conclusive evidence that aggregation rate alone cannot be used to measure affinity between nanoparticle systems with different stabilizing linkers. This is significant, as turbidimetry is widely used to demonstrate glycomaterial activity, although this work shows the most aggregating may not be the most avid, when comparing different polymer backbones/coating. Overall, our findings underline the potential of PHPMA as the coating of choice for applications where aggregation upon lectin binding would be problematic, such as in vivo imaging or drug delivery.

Therapeutic Targeting of Neutrophil Granulocytes in Inflammatory Liver Disease

Neutrophil granulocytes are the most numerous type of leukocyte in humans bearing an enormous, yet largely unexplored therapeutic potential. Scientists have very recently increased their efforts to study and understand these cells which contribute to various types of inflammatory diseases and cancer. The mechanisms that regulate neutrophil recruitment to inflamed tissues and neutrophil cytotoxic activities against host tissues and pathogens require more attention. The reactive oxygen species (ROS) are a popular source of cellular stress and organ injury, and are critically expressed by neutrophils. By combating pathogens using molecular combat factors such as neutrophil extracellular traps (NETs), these are immobilized and killed i.e., by ROS. NETs and ROS are essential for the immune defense, but upon excessive activation, may also harm healthy tissue. Thus, exploring new routes for modulating their migration and activation is highly desired for creating novel anti-inflammatory treatment options. Leukocyte transmigration represents a key process for inflammatory cell infiltration to injury sites. In this review, we briefly summarize the differentiation and roles of neutrophils, with a spotlight on intravital imaging. We further discuss the potential of nanomedicines, i.e., selectin mimetics to target cell migration and influence liver disease outcome in animal models. Novel perspectives further arise from formulations of the wide array of options of small non-coding RNA such as small interfering RNA (siRNA) and micro-RNA (miR) which exhibit enzymatic functions: while siRNA binds and degrades a single mRNA based on full complementarity of binding, miR can up and down-regulate multiple targets in gene transcription and translation, mediated by partial complementarity of binding. Notably, miR is known to regulate at least 60% of the protein-coding genes and thus includes a potent strategy for a large number of targets in neutrophils. Nanomedicines can combine properties of different drugs in a single formulation, i.e., combining surface functionalization with ligands and drug delivery. Inevitably, nanomedicines accumulate in other phagocytes, a fact that should be controlled for every novel formulation to restrain activation of macrophages or modifications of the immunological synapse. Controlled drug release enabled by nanotechnological delivery systems may advance the options of modulating neutrophil activation and migration.

Golgi Apparatus-Targeted Chondroitin-Modified Nanomicelles Suppress Hepatic Stellate Cell Activation for the Management of Liver Fibrosis

Liver fibrosis is a serious liver disease associated with high morbidity and mortality. The activation of hepatic stellate cells (HSCs) and the overproduction of extracellular matrix proteins are key features during disease progression. In this work, chondroitin sulfate nanomicelles (CSmicelles) were developed as a delivery system targeting HSCs for the treatment of liver fibrosis. CS-deoxycholic acid conjugates (CS-DOCA) were synthesized via amide bond formation. Next, retinoic acid (RA) and doxorubicin (DOX) were encapsulated into CSmicells to afford a DOX+RA-CSmicelles codelivery system. CSmicelles were selectively taken up in activated HSCs and hepatoma (HepG2) cells other than in normal hepatocytes (LO2), the internalization of which was proven to be mediated by CD44 receptors. Interestingly, DOX+RA-CSmicelles preferentially accumulated in the Golgi apparatus, destroyed the Golgi structure, and ultimately downregulated collagen I production. Following tail-vein injection, DOX+RA-CSmicelles were delivered to the cirrhotic liver and showed synergistic antifibrosis effects in the CCl₄-induced fibrotic rat model. Further, immunofluorescence staining of dissected liver tissues revealed CD44-specific delivery of CS derivatives to activated HSCs. Together, our results demonstrate the great potential of CS based carrier systems for the targeted treatment of chronic liver diseases.

A Molecular Targeted Immunotherapeutic Strategy for Ulcerative Colitis via Dual-targeting Nanoparticles Delivering miR-146b to Intestinal Macrophages

BACKGROUND AND AIMS

Macrophages are a promising therapeutic target for intestinal mucosal repair. MiR-146b appears to control macrophage activation and cell proliferation.

METHODS

By loading miR-146b mimic on mannose-modified trimethyl chitosan [MTC]-conjugated nanoparticles [NPs] [MTC-miR146b], a molecular targeted immunotherapeutic approach was developed to selectively target intestinal macrophages for mucosal regeneration and tumourigenesis in mouse models.

RESULTS

We first confirmed that miR-146b expression was significantly enhanced during mucosal regeneration in a murine colitis model. Moreover， after mucosal damage, MTC-miR146b mimic-treated wild-type mice had dramatically restored body weight and mucosal barrier function compared with MTC-NC treated mice. Strikingly, MTC-miR146b mimic oral administration protected miR-146b-deficient mice from dextran sodium sulphate [DSS] injury and the colitis-associated cancer process. Mechanistically, miR-146b strongly inhibited M1 macrophage activation by suppressing the Toll-like receptor 4 [TLR4] signalling pathway, resulting in the repression of the induction of pro-inflammatory cytokines including TNF-α, IL-6, and IL-1β. More importantly, miR-146b overexpression in bone marrow-derived macrophages [BMDMs] in M1 differentiation conditions induced a phenotype similar to M2 macrophages and improved the proliferation of co-cultured colonic epithelial cells via STAT3-dependent IL-10 production.

CONCLUSIONS

MTC-miR146b should be regarded as an effective candidate for oral delivery and could improve the efficacy of immunotherapies for ulcerative colitis and colitis-associated cancer.

Copolymers containing carbohydrates and other biomolecules: design, synthesis and applications

This review highlights recent progress in random and block copolymers containing sugar and other biocompounds, including their design, synthesis, properties and selected applications.

Biorecognition: A key to drug-free macromolecular therapeutics

This review highlights a new paradigm in macromolecular nanomedicine - drug-free macromolecular therapeutics (DFMT). The effectiveness of the new system is based on biorecognition events without the participation of low molecular weight drugs. Apoptosis of cells can be initiated by the biorecognition of complementary peptide/oligonucleotide motifs at the cell surface resulting in the crosslinking of slowly internalizing receptors. B-cell CD20 receptors and Non-Hodgkin lymphoma (NHL) were chosen as the first target. Exposing cells to a conjugate of one motif with a targeting ligand decorates the cells with this motif. Further exposure of decorated cells to a macromolecule (synthetic polymer or human serum albumin) containing multiple copies of the complementary motif as grafts results in receptor crosslinking and apoptosis induction in vitro and in vivo. The review focuses on recent developments and explores the mechanism of action of DFMT. The altered molecular signaling pathways demonstrated the great potential of DFMT to overcome rituximab resistance resulting from either down-regulation of CD20 or endocytosis and trogocytosis of rituximab/CD20 complexes. The suitability of this approach for the treatment of blood borne cancers is confirmed. In addition, the widespread applicability of DFMT as a new concept in macromolecular therapeutics for numerous diseases is exposed.