Metabolic and immunomodulatory control of type 1 diabetes via orally delivered bile-acid-polymer nanocarriers of insulin or rapamycin.

Oral formulations of insulin are typically designed to improve its intestinal absorption and increase its blood bioavailability. Here we show that polymerized ursodeoxycholic acid, selected from a panel of bile-acid polymers and formulated into nanoparticles for the oral delivery of insulin, restored blood-glucose levels in mice and pigs with established type 1 diabetes. The nanoparticles functioned as a protective insulin carrier and as a high-avidity bile-acid-receptor agonist, increased the intestinal absorption of insulin, polarized intestinal macrophages towards the M2 phenotype, and preferentially accumulated in the pancreas of the mice, binding to the islet-cell bile-acid membrane receptor TGR5 with high avidity and activating the secretion of glucagon-like peptide and of endogenous insulin. In the mice, the nanoparticles also reversed inflammation, restored metabolic functions and extended animal survival. When encapsulating rapamycin, they delayed the onset of diabetes in mice with chemically induced pancreatic inflammation. The metabolic and immunomodulatory functions of ingestible bile-acid-polymer nanocarriers may offer translational opportunities for the prevention and treatment of type 1 diabetes.

Strategies to Use Nanoparticles to Generate CD4 and CD8 Regulatory T Cells for the Treatment of SLE and Other Autoimmune Diseases.

Autoimmune diseases are disorders of immune regulation where the mechanisms responsible for self-tolerance break down and pathologic T cells overcome the protective effects of T regulatory cells (Tregs) that normally control them. The result can be the initiation of chronic inflammatory diseases. Systemic lupus erythematosus (SLE) and other autoimmune diseases are generally treated with pharmacologic or biological agents that have broad suppressive effects. These agents can halt disease progression, yet rarely cure while carrying serious adverse side effects. Recently, nanoparticles have been engineered to correct homeostatic regulatory defects and regenerate therapeutic antigen-specific Tregs. Some approaches have used nanoparticles targeted to antigen presenting cells to switch their support from pathogenic T cells to protective Tregs. Others have used nanoparticles targeted directly to T cells for the induction and expansion of CD4+ and CD8+ Tregs. Some of these T cell targeted nanoparticles have been formulated to act as tolerogenic artificial antigen presenting cells. This article discusses the properties of these various nanoparticle formulations and the strategies to use them in the treatment of autoimmune diseases. The restoration and maintenance of Treg predominance over effector cells should promote long-term autoimmune disease remission and ultimately prevent them in susceptible individuals.

Nanoparticles Engineered as Artificial Antigen-Presenting Cells Induce Human CD4+ and CD8+ Tregs That Are Functional in Humanized Mice.

Artificial antigen-presenting cells (aAPCs) are synthetic versions of naturally occurring antigen-presenting cells (APCs) that, similar to natural APCs, promote efficient T effector cell responses in vitro. This report describes a method to produce acellular tolerogenic aAPCs made of biodegradable poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) and encapsulating IL-2 and TGF-ß for a paracrine release to T cells. We document that these aAPCs can induce both human CD4+ and CD8+ T cells to become FoxP3+ T regulatory cells (Tregs). The aAPC NP-expanded human Tregs are functional in vitro and can modulate systemic autoimmunity in vivo in humanized NSG mice. These findings establish a proof-of-concept to use PLGA NPs as aAPCs for the induction of human Tregs in vitro and in vivo, highlighting the immunotherapeutic potential of this targeted approach to repair IL-2 and/or TGF-ß defects documented in certain autoimmune diseases such as systemic lupus erythematosus.

Direct Comparison of B Cell Surface Receptors as Therapeutic Targets for Nanoparticle Delivery of BTK Inhibitors.

Targeting different cell surface receptors with nanoparticle (NP)-based platforms can result in differential particle binding properties that may impact their localization, bioavailability, and, ultimately, the therapeutic efficacy of an encapsulated payload. Conventional in vitro assays comparing the efficacy of targeted NPs often do not adequately control for these differences in particle-receptor binding, potentially confounding their therapeutic readouts and possibly even limiting their experimental value. In this work, we characterize the conditions under which NPs loaded with Bruton's Tyrosine Kinase (BTK) inhibitor differentially suppress primary B cell activation when targeting either CD19 (internalizing) or B220 (noninternalizing) surface receptors. Surface binding of fluorescently labeled CD19- and B220-targeted NPs was analyzed and quantitatively correlated with the number of bound particles at given treatment concentrations. Using this binding data, suppression of B cell activation was directly compared for differentially targeted (CD19 vs B220) NPs loaded with a BTK inhibitor at a range of particle drug loading concentrations. When NPs were loaded with lower amounts of drug, CD19-mediated internalization demonstrated increased inhibition of B cell proliferation compared with B220 NPs. However, these differences were mitigated when particles were loaded with higher concentrations of BTK inhibitor and B220-mediated "paracrine-like" delivery demonstrated superior suppression of cellular activation when cells were bound to lower overall numbers of NPs. Taken together, these results demonstrate that inhibition of B cell activation can be optimized for NPs targeting either internalizing or noninternalizing surface receptors and that particle internalization is likely not a requisite endpoint when designing particles for delivery of BTK inhibitor to B cells.

Multiple Sclerosis: LIFNano-CD4 for Trojan Horse Delivery of the Neuro-Protective Biologic "LIF" Into the Brain: Preclinical Proof of Concept.

Multiple sclerosis (MS) is a demyelinating autoimmune disease that attacks the brain, with year-on-year loss of brain volume, starting late teens and becoming manifest late twenties. There is no cure, and current therapies are immunosuppressive only. LIF is a vital stem cell growth factor active throughout life-and essential for health of the central nervous system (CNS), being tolerogenic, myelinogenic, and neuroprotective. Nano-formulation of LIF (LIFNano) using FDA-approved PLGA captures LIF's compound therapeutic properties, increasing potency 1,000-fold when targeted to CD4 (LIFNano-CD4). Moreover, circulating CD4+ lymphocytes are themselves regulated by LIF to express the Treg phenotype, known to release T cell-derived LIF upon engagement with cognate antigen, perpetuating antigen-specific self-tolerance. With the longer-term aim of treating inflammatory lesions of MS, we asked, does LIFNano-CD4 cross the blood-brain barrier (BBB)? We measure pK and pD using novel methodologies, demonstrate crossing of the BBB, show LIF-cargo-specific anti-inflammatory efficacy in the frontal cortex of the brain, and show safety of intravenous delivery of LIFNano-CD4 at doses known to provide efficacious concentrations of LIF cargo behind the BBB.

Nanoparticle-mediated Delivery of IL-2 To T Follicular Helper Cells Protects BDF1 Mice from Lupus-like Disease.

We recently reported that poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) loaded with interleukin (IL)-2 and targeted to T cells inhibited the development of lupus-like disease in BDF1 mice by inducing functional T regulatory cells (Tregs). Here we show that the protection from disease and the extended survival of BDF1 mice provided by IL-2-loaded NPs targeted to T cells is not only due to an induction of Tregs but also contributed by an inhibition of T follicular helper (TFH) cells. These results identify a dual protective activity of IL-2 in the control of lupus autoimmunity, namely the inhibition of effector TFH cells, in addition to the previously known induction of Tregs. This newly recognized activity of IL-2 delivered by NPs can help better explain the beneficial effects of low-dose IL-2 immunotherapy in systemic lupus erythematosus (SLE), and might be considered as a new strategy to slow disease progression and improve outcomes in lupus patients.

Anti-CD2 Antibody-Coated Nanoparticles Containing IL-2 Induce NK Cells That Protect Lupus Mice via a TGF-ß-Dependent Mechanism.

We recently reported that the treatment with nanoparticles (NPs) loaded with tolerogenic cytokines suppressed the manifestations of lupus-like disease induced by the transfer of donor CD4+ T cells from DBA/2 mice into (C57BL/6 × DBA/2)F1 (BDF1) mice. Although the protective effects were ascribed to the induction of adaptive CD4+ and CD8+ T regulatory cells, the results suggested that another population of immune cells could be involved. Here we report that NK cells critically contribute to the protection from lupus-like disease conferred by NPs to BDF1 mice, and that this effect is TGF-ß-dependent.

Suppression of Murine Lupus by CD4+ and CD8+ Treg Cells Induced by T Cell-Targeted Nanoparticles Loaded With Interleukin-2 and Transforming Growth Factor ß.

OBJECTIVE: To develop a nanoparticle (NP) platform that can expand both CD4+ and CD8+ Treg cells in vivo for the suppression of autoimmune responses in systemic lupus erythematosus (SLE). METHODS: Poly(lactic-co-glycolic acid) (PLGA) NPs encapsulating interleukin-2 (IL-2) and transforming growth factor ß (TGFß) were coated with anti-CD2/CD4 antibodies and administered to mice with lupus-like disease induced by the transfer of DBA/2 T cells into (C57BL/6 × DBA/2)F1 (BDF1) mice. The peripheral frequency of Treg cells was monitored ex vivo by flow cytometry. Disease progression was assessed by measuring serum anti-double-stranded DNA antibody levels by enzyme-linked immunosorbent assay. Kidney disease was defined as the presence of proteinuria or renal histopathologic features. RESULTS: Anti-CD2/CD4 antibody-coated, but not noncoated, NPs encapsulating IL-2 and TGFß induced CD4+ and CD8+ FoxP3+ Treg cells in vitro. The optimal dosing regimen of NPs for expansion of CD4+ and CD8+ Treg cells was determined in in vivo studies in mice without lupus and then tested in BDF1 mice with lupus. The administration of anti-CD2/CD4 antibody-coated NPs encapsulating IL-2 and TGFß resulted in the expansion of CD4+ and CD8+ Treg cells, a marked suppression of anti-DNA antibody production, and reduced renal disease. CONCLUSION: This study shows for the first time that T cell-targeted PLGA NPs encapsulating IL-2 and TGFß can expand both CD4+ and CD8+ Treg cells in vivo and suppress murine lupus. This approach, which enables the expansion of Treg cells in vivo and inhibits pathogenic immune responses in SLE, could represent a potential new therapeutic modality in autoimmune conditions characterized by impaired Treg cell function associated with IL-2 deficiency.

Precision DNA demethylation ameliorates disease in lupus-prone mice.

Defective DNA methylation in T cells leads to a series of T cell abnormalities in lupus; however, the full effect of T cell lineage-specific DNA methylation on disease expression has not been explored. Here, we show that 5-azacytidine, a DNA methyltransferase inhibitor, targeted to either CD4 or CD8 T cells in mice with established disease using a nanolipogel delivery system dramatically ameliorates lupus-related pathology through distinct mechanisms. In vivo targeted delivery of 5-azacytidine into CD4 T cells favors the expansion and function of Foxp3+ Tregs, whereas targeted delivery to CD8 T cells enhances the cytotoxicity and restrains the expansion of pathogenic TCR-αß+CD4-CD8- double-negative T cells. Our results signify the importance of cell-specific inhibition of DNA methylation in the treatment of established lupus.

CaMK4 compromises podocyte function in autoimmune and nonautoimmune kidney disease.

Podocyte malfunction occurs in autoimmune and nonautoimmune kidney disease. Calcium signaling is essential for podocyte injury, but the role of Ca2+/calmodulin-dependent kinase (CaMK) signaling in podocytes has not been fully explored. We report that podocytes from patients with lupus nephritis and focal segmental glomerulosclerosis and lupus-prone and lipopolysaccharide- or adriamycin-treated mice display increased expression of CaMK IV (CaMK4), but not CaMK2. Mechanistically, CaMK4 modulated podocyte motility by altering the expression of the GTPases Rac1 and RhoA and suppressed the expression of nephrin, synaptopodin, and actin fibers in podocytes. In addition, it phosphorylated the scaffold protein 14-3-3ß, which resulted in the release and degradation of synaptopodin. Targeted delivery of a CaMK4 inhibitor to podocytes preserved their ultrastructure, averted immune complex deposition and crescent formation, and suppressed proteinuria in lupus-prone mice and proteinuria in mice exposed to lipopolysaccharide-induced podocyte injury by preserving nephrin/synaptopodin expression. In animals exposed to adriamycin, podocyte-specific delivery of a CaMK4 inhibitor prevented and reversed podocyte injury and renal disease. We conclude that CaMK4 is pivotal in immune and nonimmune podocyte injury and that its targeted cell-specific inhibition preserves podocyte structure and function and should have therapeutic value in lupus nephritis and podocytopathies, including focal segmental glomerulosclerosis.

Neurodegenerative Disease: A Perspective on Cell-Based Therapy in the New Era of Cell-Free Nano-Therapy.

Neurodegenerative diseases (NDD) result in irreversible loss of neurons. Dementia develops when disease-induced neuronal loss becomes sufficient to impair both memory and cognitive functioning and, globally, dementia is increasing to epidemic proportions as populations age. In the current era of regenerative medicine intense activity is asking, can loss of endogenous neurons be compensated by replacement with exogenously derived cells that have either direct, or indirect, neurogenic capacity? But, more recently, excitement is growing around an emerging alternative to the cell-based approach - here nanotechnology for targeted delivery of growth factor aims to support and expand resident central nervous system (CNS) stem cells for endogenous repair. The concept of a high volume, off-the-shelf nano-therapeutic able to rejuvenate the endogenous neuroglia of the CNS is highly attractive, providing a simple solution to the complex challenges posed by cell-based regenerative medicine. The role of inflammation as an underlying driver of NDD is also considered where anti-inflammatory approaches are candidates for therapy. Indeed, cell-based therapy and/or nanotherapy may protect against inflammation to support both immune quiescence and neuronal survival in the CNS - key targets for treating NDD with the potential to reduce or even stop the cascading pathogenesis and disease progression, possibly promoting some repair where disease is treated early. By design, nanoparticles can be formulated to cross the blood brain barrier (BBB) enabling sustained delivery of neuro-protective agents for sufficient duration to reset neuro-immune homeostasis. Proven safe and efficacious, it is now urgent to deliver nano-medicine (NanoMed) as a scalable approach to treat NDD, where key stakeholders are the patients and the global economy.

Cutting Edge: Nanogel-Based Delivery of an Inhibitor of CaMK4 to CD4+ T Cells Suppresses Experimental Autoimmune Encephalomyelitis and Lupus-like Disease in Mice.

Treatment of autoimmune diseases is still largely based on the use of systemically acting immunosuppressive drugs, which invariably cause severe side effects. Calcium/calmodulin-dependent protein kinase IV is involved in the suppression of IL-2 and the production of IL-17. Its pharmacologic or genetic inhibition limits autoimmune disease in mice. In this study, we demonstrate that KN93, a small-molecule inhibitor of calcium/calmodulin-dependent protein kinase IV, targeted to CD4(+) T cells via a nanolipogel delivery system, markedly reduced experimental autoimmune encephalomyelitis and was 10-fold more potent than the free systemically delivered drug in the lupus mouse models. The targeted delivery of KN93 did not deplete T cells but effectively blocked Th17 cell differentiation and expansion as measured in the spinal cords and kidneys of mice developing experimental autoimmune encephalomyelitis or lupus, respectively. These results highlight the promise of cell-targeted inhibition of molecules involved in the pathogenesis of autoimmunity as a means of advancing the treatment of autoimmune diseases.

Interconnected roles of scaffold hydrophobicity, drug loading, and encapsulation stability in polymeric nanocarriers.

Polymer-based nanoassemblies have emerged as viable platforms for the encapsulation and delivery of lipophilic molecules. Among the criteria that such carriers must meet, if they are to be effective, are the abilities to efficiently solubilize lipophilic guests within an assembled scaffold and to stably encapsulate the molecular cargo until desired release is achieved through the actions of appropriately chosen stimuli. The former feature, dictated by the inherent loading capacity of a nanocarrier, is well studied, and it has been established that slight variations in assembly structure, such as introducing hydrophobic content, can improve miscibility with the lipophilic guests and increase the driving force for encapsulation. However, such clear correlations between assembly properties and the latter feature, nanocarrier encapsulation stability, are not yet established. For this purpose, we have investigated the effects of varying hydrophobic content on the loading parameters and encapsulation stabilities of self-cross-linked polymer nanogels. Through investigating this nanogel series, we have observed a fundamental relationship between nanoassembly structure, loading capacity, and encapsulation stability. Furthermore, a combined analysis of data from different loading amounts suggests a model of loading-dependent encapsulation stability that underscores an important correlation between the principal features of noncovalent encapsulation in supramolecular hosts.

Ligand-decorated nanogels: fast one-pot synthesis and cellular targeting.

Nanoscale vehicles for delivery have been of interest and extensively studied for two decades. However, the encapsulation stability of hydrophobic drug molecules in delivery vehicles and selective targeting these vehicles into disease cells are potential hurdles for efficient delivery systems. Here we demonstrate a simple and fast synthetic protocol of nanogels that shows high encapsulation stabilities. These nanogels can also be modified with various targeting ligands for active targeting. We show that the targeting nanogels (T-NGs), which are prepared within 2 h by a one-pot synthesis, exhibit very narrow size distributions and have the versatility of surface modification with cysteine-modified ligands including folic acid, cyclic arginine-glycine-aspartic acid (cRGD) peptide, and cell-penetrating peptide. T-NGs hold their payloads, undergo facilitated cell internalization by receptor-mediated uptake, and release their drug content inside cells due to the reducing intracellular environment. Selective cytotoxicity to cells, which have complementary receptors, is also demonstrated.

Self-cross-linked polymer nanogels: a versatile nanoscopic drug delivery platform.

Nanoscopic vehicles that stably encapsulate drug molecules and release them in response to a specific trigger are of great interest due to implications in therapeutic applications, especially for cancer therapy. For this purpose, we have synthesized highly stable polymeric nanogels, in which the kinetics of guest molecule release can be fine-tuned by control over cross-linking density. The polymer nanogel precursor is based on a random copolymer that contains oligoethyleneglycol (OEG) and pyridyldisulfide (PDS) units as side-chain functionalities. By introducing variations into the precursor polymer, such as molecular weight and the relative percentages of hydrophilic OEG units and hydrophobic PDS functionalities, we have achieved significant control over nanogel size. We show that the noncovalently encapsulated guest molecules can be released in response to a redox trigger, glutathione (GSH). Stability of dye encapsulation inside the nanogels and tunability in the release of guest molecules have been demonstrated through in vitro fluorescence resonance energy transfer (FRET) experiments. We show in vitro doxorubicin delivery into breast cancer cells (MCF-7) with nanogels of different cross-linking density to demonstrate that it plays a key role in the stable encapsulation of hydrophobic drug molecules and the cell-uptake efficiencies.

Noncovalent encapsulation stabilities in supramolecular nanoassemblies.

Exchange dynamics of lipophilic guest molecules, encapsulated in supramolecular nanoassemblies in aqueous solutions, have implications in evaluating the stability of drug delivery vehicles. This is because exchange dynamics is related to the propensity of a nanocarrier to be leaky. We describe a fluorescence resonance energy transfer (FRET) based method to evaluate guest exchange dynamics in the aqueous phase. We have utilized this method to analyze the stability of encapsulation in polymeric nanogels and other related amphiphilic nanoassemblies.

Surface-functionalizable polymer nanogels with facile hydrophobic guest encapsulation capabilities.

The stability of encapsulation in self-assembly systems is limited during blood circulation because of a requisite concentration for assembly formation. For deliberate molecular design for stable encapsulation, targeting, and triggered release, we have developed a facile synthetic method for highly stable, polymeric nanogels using a simple intra/interchain cross-linking reaction. We show a simple, emulsion-free method for the preparation of biocompatible nanogels that provides the ability to encapsulate hydrophobic guest molecules and surface functionalization which has potential for targeted delivery. We show that the noncovalently encapsulated guest molecules can be released in response to a biologically relevant stimulus.