ABCD of IA: A multi-scale agent-based model of T cell activation in inflammatory arthritis.

Biomaterial-based agents have been demonstrated to regulate the function of immune cells in models of autoimmunity. However, the complexity of the kinetics of immune cell activation can present a challenge in optimizing the dose and frequency of administration. Here, we report a model of autoreactive T cell activation, which are key drivers in autoimmune inflammatory joint disease. The model is termed a multi-scale Agent-Based, Cell-Driven model of Inflammatory Arthritis (ABCD of IA). Using kinetic rate equations and statistical theory, ABCD of IA simulated the activation and presentation of autoantigens by dendritic cells, interactions with cognate T cells and subsequent T cell proliferation in the lymph node and IA-affected joints. The results, validated with in vivo data from the T cell driven SKG mouse model, showed that T cell proliferation strongly correlated with the T cell receptor (TCR) affinity distribution (TCR-ad), with a clear transition state from homeostasis to an inflammatory state. T cell proliferation was strongly dependent on the amount of antigen in antigenic stimulus event (ASE) at low concentrations. On the other hand, inflammation driven by Th17-inducing cytokine mediated T cell phenotype commitment was influenced by the initial level of Th17-inducing cytokines independent of the amount of arthritogenic antigen. The introduction of inhibitory artificial antigen presenting cells (iaAPCs), which locally suppress T cell activation, reduced T cell proliferation in a dose-dependent manner. The findings in this work set up a framework based on theory and modeling to simulate personalized therapeutic strategies in IA.

The therapeutic potential of immunoengineering for systemic autoimmunity.

Disease-modifying drugs have transformed the treatment options for many systemic autoimmune diseases. However, an evolving understanding of disease mechanisms, which might vary between individuals, is paving the way for the development of novel agents that operate in a patient-tailored manner through immunophenotypic regulation of disease-relevant cells and the microenvironment of affected tissue domains. Immunoengineering is a field that is focused on the application of engineering principles to the modulation of the immune system, and it could enable future personalized and immunoregulatory therapies for rheumatic diseases. An important aspect of immunoengineering is the harnessing of material chemistries to design technologies that span immunologically relevant length scales, to enhance or suppress immune responses by re-balancing effector and regulatory mechanisms in innate or adaptive immunity and rescue abnormalities underlying pathogenic inflammation. These materials are endowed with physicochemical properties that enable features such as localization in immune cells and organs, sustained delivery of immunoregulatory agents, and mimicry of key functions of lymphoid tissue. Immunoengineering applications already exist for disease management, and there is potential for this new discipline to improve disease modification in rheumatology.

Immunomodulatory Nanoparticles for Modulating Arthritis Flares.

Disease-modifying drugs have improved the treatment for autoimmune joint disorders, such as rheumatoid arthritis, but inflammatory flares are a common experience. This work reports the development and application of flare-modulating poly(lactic-co-glycolic acid)-poly(ethylene glycol)-maleimide (PLGA-PEG-MAL)-based nanoparticles conjugated with joint-relevant peptide antigens, aggrecan70-84 and type 2 bovine collagen256-270. Peptide-conjugated PLGA-PEG-MAL nanoparticles encapsulated calcitriol, which acted as an immunoregulatory agent, and were termed calcitriol-loaded nanoparticles (CLNP). CLNP had a ∼200 nm hydrodynamic diameter with a low polydispersity index. In vitro, CLNP induced phenotypic changes in bone marrow derived dendritic cells (DC), reducing the expression of costimulatory and major histocompatibility complex class II molecules, and proinflammatory cytokines. Bulk RNA sequencing of DC showed that CLNP enhanced expression of Ctla4, a gene associated with downregulation of immune responses. In vivo, CLNP accumulated in the proximal lymph nodes after intramuscular injection. Administration of CLNP was not associated with changes in peripheral blood cell numbers or cytokine levels. In the collagen-induced arthritis and SKG mouse models of autoimmune joint disorders, CLNP reduced clinical scores, prevented bone erosion, and preserved cartilage proteoglycan, as assessed by high-resolution microcomputed tomography and histomorphometry analysis. The disease protective effects were associated with increased CTLA-4 expression in joint-localized DC and CD4+ T cells but without generalized suppression of T cell-dependent immune response. The results support the potential of CLNP as modulators of disease flares in autoimmune arthropathies.

Biodegradable scaffolds for enhancing vaccine delivery.

Sustained release of vaccine components is a potential method to boost efficacy compared with traditional bolus injection. Here, we show that a biodegradable hyaluronic acid (HA)-scaffold, termed HA cryogel, mediates sustained antigen and adjuvant release in vivo leading to a durable immune response. Delivery from subcutaneously injected HA cryogels was assessed and a formulation which enhanced the immune response while minimizing the inflammation associated with the foreign body response was identified, termed CpG-OVA-HAC2. Dose escalation studies with CpG-OVA-HAC2 demonstrated that both the antibody and T cell responses were dose-dependent and influenced by the competency of neutrophils to perform oxidative burst. In immunodeficient post-hematopoietic stem cell transplanted mice, immunization with CpG-OVA-HAC2 elicited a strong antibody response, three orders of magnitude higher than dose-matched bolus injection. In a melanoma model, CpG-OVA-HAC2 induced dose-responsive prophylactic protection, slowing the tumor growth rate and enhancing overall survival. Upon rechallenge, none of the mice developed new tumors suggesting the development of robust immunological memory and long-lasting protection against repeat infections. CpG-OVA-HAC2 also enhanced survival in mice with established tumors. The results from this work support the potential for CpG-OVA-HAC2 to enhance vaccine delivery.

Immunomodulatory Microparticles Epigenetically Modulate T Cells and Systemically Ameliorate Autoimmune Arthritis.

Disease modifying antirheumatic drugs (DMARDs) have improved the prognosis of autoimmune inflammatory arthritides but a large fraction of patients display partial or nonresponsiveness to front-line DMARDs. Here, an immunoregulatory approach based on sustained joint-localized release of all-trans retinoic acid (ATRA), which modulates local immune activation and enhances disease-protective T cells and leads to systemic disease control is reported. ATRA imprints a unique chromatin landscape in T cells, which is associated with an enhancement in the differentiation of naïve T cells into anti-inflammatory regulatory T cells (Treg ) and suppression of Treg destabilization. Sustained release poly-(lactic-co-glycolic) acid (PLGA)-based biodegradable microparticles encapsulating ATRA (PLGA-ATRA MP) are retained in arthritic mouse joints after intra-articular (IA) injection. IA PLGA-ATRA MP enhance migratory Treg which in turn reduce inflammation and modify disease in injected and uninjected joints, a phenotype that is also reproduced by IA injection of Treg . PLGA-ATRA MP reduce proteoglycan loss and bone erosions in the SKG and collagen-induced arthritis mouse models of autoimmune arthritis. Strikingly, systemic disease modulation by PLGA-ATRA MP is not associated with generalized immune suppression. PLGA-ATRA MP have the potential to be developed as a disease modifying agent for autoimmune arthritis.

Immune-responsive biodegradable scaffolds for enhancing neutrophil regeneration.

Neutrophils are essential effector cells for mediating rapid host defense and their insufficiency arising from therapy-induced side-effects, termed neutropenia, can lead to immunodeficiency-associated complications. In autologous hematopoietic stem cell transplantation (HSCT), neutropenia is a complication that limits therapeutic efficacy. Here, we report the development and in vivo evaluation of an injectable, biodegradable hyaluronic acid (HA)-based scaffold, termed HA cryogel, with myeloid responsive degradation behavior. In mouse models of immune deficiency, we show that the infiltration of functional myeloid-lineage cells, specifically neutrophils, is essential to mediate HA cryogel degradation. Post-HSCT neutropenia in recipient mice delayed degradation of HA cryogels by up to 3 weeks. We harnessed the neutrophil-responsive degradation to sustain the release of granulocyte colony stimulating factor (G-CSF) from HA cryogels. Sustained release of G-CSF from HA cryogels enhanced post-HSCT neutrophil recovery, comparable to pegylated G-CSF, which, in turn, accelerated cryogel degradation. HA cryogels are a potential approach for enhancing neutrophils and concurrently assessing immune recovery in neutropenic hosts.

Short-chain fatty acid-mediated epigenetic modulation of inflammatory T cells in vitro.

Short-chain fatty acids (SCFAs) are major metabolic products of indigestible polysaccharides in the gut and mediate the function of immune cells to facilitate homeostasis. The immunomodulatory effect of SCFAs has been attributed, at least in part, to the epigenetic modulation of immune cells through the inhibition the nucleus-resident enzyme histone deacetylase (HDAC). Among the downstream effects, SCFAs enhance regulatory T cells (Treg) over inflammatory T helper (Th) cells, including Th17 cells, which can be pathogenic. Here, we characterize the potential of two common SCFAs-butyrate and pentanoate-in modulating differentiation of T cells in vitro. We show that butyrate but not pentanoate exerts a concentration-dependent effect on Treg and Th17 differentiation. Increasing the concentration of butyrate suppresses the Th17-associated RORγtt and IL-17 and increases the expression of Treg-associated FoxP3. To effectively deliver butyrate, encapsulation of butyrate in a liposomal carrier, termed BLIPs, reduced cytotoxicity while maintaining the immunomodulatory effect on T cells. Consistent with these results, butyrate and BLIPs inhibit HDAC and promote a unique chromatin landscape in T cells under conditions that otherwise promote conversion into a pro-inflammatory phenotype. Motif enrichment analysis revealed that butyrate and BLIP-mediated suppression of Th17-associated chromatin accessibility corresponded with a marked decrease in bZIP family transcription factor binding sites. These results support the utility and further evaluation of BLIPs as an immunomodulatory agent for autoimmune disorders that are characterized by chronic inflammation and pathogenic inflammatory T cells.

3D-Bioprinted Phantom with Human Skin Phototypes for Biomedical Optics.

3D-bioprinted skin-mimicking phantoms with skin colors ranging across the Fitzpatrick scale are reported. These tools can help understand the impact of skin phototypes on biomedical optics. Synthetic melanin nanoparticles of different sizes (70-500 nm) and clusters are fabricated to mimic the optical behavior of melanosome. The absorption coefficient and reduced scattering coefficient of the phantoms are comparable to real human skin. Further the melanin content and distribution in the phantoms versus real human skins are validated via photoacoustic (PA) imaging. The PA signal of the phantom can be improved by: 1) increasing melanin size (3-450-fold), 2) increasing clustering (2-10.5-fold), and 3) increasing concentration (1.3-8-fold). Then, multiple biomedical optics tools (e.g., PA, fluorescence imaging, and photothermal therapy) are used to understand the impact of skin tone on these modalities. These well-defined 3D-bioprinted phantoms may have value in translating biomedical optics and reducing racial bias.

Lipid-based regulators of immunity.

Lipids constitute a diverse class of molecular regulators with ubiquitous physiological roles in sustaining life. These carbon-rich compounds are primarily sourced from exogenous sources and may be used directly as structural cellular building blocks or as a substrate for generating signaling mediators to regulate cell behavior. In both of these roles, lipids play a key role in both immune activation and suppression, leading to inflammation and resolution, respectively. The simple yet elegant structural properties of lipids encompassing size, hydrophobicity, and molecular weight enable unique biodistribution profiles that facilitate preferential accumulation in target tissues to modulate relevant immune cell subsets. Thus, the structural and functional properties of lipids can be leveraged to generate new materials as pharmacological agents for potently modulating the immune system. Here, we discuss the properties of three classes of lipids: polyunsaturated fatty acids, short-chain fatty acids, and lipid adjuvants. We describe their immunoregulatory functions in modulating disease pathogenesis in preclinical models and in human clinical trials. We conclude with an outlook on harnessing the diverse and potent immune modulating properties of lipids for immunoregulation.

Triggers, Timescales, and Treatments for Cytokine-Mediated Tissue Damage.

Inflammation is an essential cytokine-mediated process for generating a neutralizing immune response against pathogens and is generally protective. However, aberrant or excessive production of pro-inflammatory cytokines is associated with uncontrolled local and systemic inflammation, resulting in cell death and often irreversible tissue damage. Uncontrolled inflammation can manifest over timescales spanning hours to years and is primarily dependent on the triggering event. Rapid and potentially lethal increase in cytokine production, or a 'cytokine storm,' develops in hours to days and is associated with cancer cell-based immunotherapies, such as CAR-T cell therapy. On the other hand, some bacterial and viral infections with high microbial replication or highly potent antigens elicit immune responses that result in supraphysiological systemic cytokine concentrations which manifest over days to weeks. Immune dysregulation in autoimmune diseases can lead to chronic cytokine-mediated tissue damage spanning months to years, which often occurs episodically. While the initiating events and cellular participants may differ in these disease processes, many of the cytokines that drive disease progression are shared. For example, upregulation of IL-1, IL-6, IFN-γ, TNF, and GM-CSF frequently coincides with cytokine storm, sepsis, and autoimmune disease. Targeted inhibition of these pro-inflammatory molecules via antagonist monoclonal antibodies has improved clinical outcomes, but the complexity of the underlying immune dysregulation results in high variability. Rather than a "one size fits all" treatment approach, an identification of disease endotypes may permit the development of effective therapeutic strategies that address the contributors of disease progression. Here, we present a literature review of the cytokine-associated etiology of acute and chronic cytokine-mediated tissue damage, describe successes and challenges in developing clinical treatments, and highlight advancements in preclinical therapeutic strategies for mitigating pathological cytokine production.

Combining therapeutic vaccines with chemo- and immunotherapies in the treatment of cancer.

INTRODUCTION: Breakthroughs in cancer immunotherapy have spurred interest in the development of vaccines to mediate prophylactic protection and therapeutic efficacy against primary tumors or to prevent relapse. However, immunosuppressive mechanisms employed by cancer cells to generate effective resistance have hampered clinical translation of therapeutic cancer vaccines. To enhance vaccine efficacy, the immunomodulatory properties of cytoreductive therapies could amplify a cancer-specific immune response. AREAS COVERED: Herein, the authors discuss therapeutic cancer vaccines that harness whole cells and antigen-targeted vaccines. First, recent advancements in both autologous and allogeneic whole-cell vaccines and combinations with checkpoint blockade and chemotherapy are reviewed. Next, tumor antigen-targeted vaccines using peptide-based vaccines and DNA-vaccines are discussed. Finally, combination therapies using antigen-targeted vaccines are reviewed. EXPERT OPINION: A deeper understanding of the immunostimulatory properties of cytoreductive therapies has supported their utility in combination therapies involving cancer vaccines as a potential strategy to induce a durable anti-tumor immune response for multiple types of cancers. Based on current evidence, combination therapies may have synergies that depend on the identity of the cytotoxic agent, vaccine target, dosing schedule, and cancer type. Together, these observations suggest that combining cancer vaccines with immunomodulatory cytoreductive therapy is a promising strategy for cancer therapy.

Characterization of regulatory T cell expansion for manufacturing cellular immunotherapies.

Regulatory T cells (Tregs) are critical mediators of peripheral immune tolerance. Tregs suppress immune activation against self-antigens and are the focus of cell-based therapies for autoimmune diseases. However, Tregs circulate at a very low frequency in blood, limiting the number of cells that can be isolated by leukapheresis. To effectively expand Tregsex vivo for cell therapy, we report the metabolic modulation of T cells using mono-(6-amino-6-deoxy)-ß-cyclodextrin (ßCD-NH2) encapsulated rapamycin (Rapa). Encapsulating Rapa in ß-cyclodextrin increased its aqueous solubility ∼154-fold and maintained bioactivity for at least 30 days. ßCD-NH2-Rapa complexes (CRCs) enriched the fraction of CD4+CD25+FoxP3+ mouse T (mT) cells and human T (hT) cells up to 6-fold and up to 2-fold respectively and suppressed the overall expansion of effector T cells by 5-fold in both species. Combining CRCs and transforming growth factor beta-1 (TGF-ß1) synergistically promoted the expansion of CD4+CD25+FoxP3+ T cells. CRCs significantly reduced the fraction of pro-inflammatory interferon-gamma (IFN-γ) expressing CD4+ T cells, suppressing this Th1-associated cytokine while enhancing the fraction of IFN-γ- tumor necrosis factor-alpha (TNF-α) expressing CD4+ T cells. We developed a model using kinetic rate equations to describe the influence of the initial fraction of naïve T cells on the enrichment of Tregsin vitro. The model related the differences in the expansion kinetics of mT and hT cells to their susceptibility for immunophenotypic modulation. CRCs may be an effective and potent means for phenotypic modulation of T cells and the enrichment of Tregsin vitro. Our findings contribute to the development of experimental and analytical techniques for manufacturing Treg based immunotherapies.

A biomaterial-based vaccine eliciting durable tumour-specific responses against acute myeloid leukaemia.

Acute myeloid leukaemia (AML) is a malignancy of haematopoietic origin that has limited therapeutic options. The standard-of-care cytoreductive chemotherapy depletes AML cells to induce remission, but is infrequently curative. An immunosuppressive AML microenvironment in the bone marrow and the paucity of suitable immunotherapy targets limit the induction of effective immune responses. Here, in mouse models of AML, we show that a macroporous-biomaterial vaccine that delivers the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF), the Toll-like-receptor-9 agonist cytosine-guanosine oligodeoxynucleotide and one or multiple leukaemia antigens (in the form of a defined peptide antigen, cell lysates or antigens sourced from AML cells recruited in vivo) induces local immune-cell infiltration and activated dendritic cells, evoking a potent anti-AML response. The biomaterial-based vaccine prevented the engraftment of AML cells when administered as a prophylactic and when combined with chemotherapy, and eradicated established AML even in the absence of a defined vaccine antigen. Biomaterial-based AML vaccination can induce potent immune responses, deplete AML cells and prevent disease relapse.

Built-In Active Microneedle Patch with Enhanced Autonomous Drug Delivery.

The use of microneedles has facilitated the painless localized delivery of drugs across the skin. However, their efficacy has been limited by slow diffusion of molecules and often requires external triggers. Herein, an autonomous and degradable, active microneedle delivery platform is introduced, employing magnesium microparticles loaded within the microneedle patch, as the built-in engine for deeper and faster intradermal payload delivery. The magnesium particles react with the interstitial fluid, leading to an explosive-like rapid production of H2 bubbles, providing the necessary force to breach dermal barriers and enhance payload delivery. The release kinetics of active microneedles is evaluated in vitro by measuring the amount of IgG antibody (as a model drug) that passed through phantom tissue and a pigskin barrier. In vivo experiments using a B16F10 mouse melanoma model demonstrate that the active delivery of anti-CTLA-4 (a checkpoint inhibitor drug) results in greatly enhanced immune response and significantly longer survival. Moreover, spatially resolved zones of active and passive microneedles allow a combinatorial rapid burst response along with slow, sustained release, respectively. Such versatile and effective autonomous dynamic microneedle delivery technology offers considerable promise for a wide range of therapeutic applications, toward a greatly enhanced outcome, convenience, and cost.

Programmable microencapsulation for enhanced mesenchymal stem cell persistence and immunomodulation.

Mesenchymal stem cell (MSC) therapies demonstrate particular promise in ameliorating diseases of immune dysregulation but are hampered by short in vivo cell persistence and inconsistencies in phenotype. Here, we demonstrate that biomaterial encapsulation into alginate using a microfluidic device could substantially increase in vivo MSC persistence after intravenous (i.v.) injection. A combination of cell cluster formation and subsequent cross-linking with polylysine led to an increase in injected MSC half-life by more than an order of magnitude. These modifications extended persistence even in the presence of innate and adaptive immunity-mediated clearance. Licensing of encapsulated MSCs with inflammatory cytokine pretransplantation increased expression of immunomodulatory-associated genes, and licensed encapsulates promoted repopulation of recipient blood and bone marrow with allogeneic donor cells after sublethal irradiation by a ∼2-fold increase. The ability of microgel encapsulation to sustain MSC survival and increase overall immunomodulatory capacity may be applicable for improving MSC therapies in general.

Applications of molecular engineering in T-cell-based immunotherapies.

Harnessing an individual's immune cells to mediate antitumor and antiviral responses is a life-saving option for some patients with otherwise intractable forms of cancer and infectious disease. In particular, T-cell-based engineered immune cells are a powerful new class of therapeutics with remarkable efficacy. Clinical experience has helped to define some of the major challenges for reliable, safe, and effective deployment of T-cells against a broad range of diseases. While poised to revolutionize immunotherapy, scalable manufacturing, safety, specificity, and the development of resistance are potential roadblocks in their widespread usage. The development of molecular engineering tools to allow for the direct or indirect engineering of T-cells to enable one to troubleshoot delivery issues, amplify immunomodulatory effects, integrate the synergistic effects of different molecules, and home to the target cells in vivo. In this review, we will analyze thus-far developed cell- and material-based tools for enhancing T-cell therapies, including methods to improve safety and specificity, enhancing efficacy, and overcoming limitations in scalable manufacturing. We summarize the potential of T-cells as immune modulating therapies and the potential future directions for enabling their adoption for a broad range of diseases. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Cells at the Nanoscale.