Amplifying STING activation by cyclic dinucleotide-manganese particles for local and systemic cancer metalloimmunotherapy.

Nutritional metal ions play critical roles in many important immune processes. Hence, the effective modulation of metal ions may open up new forms of immunotherapy, termed as metalloimmunotherapy. Here, we demonstrate a prototype of cancer metalloimmunotherapy using cyclic dinucleotide (CDN) stimulator of interferon genes (STING) agonists and Mn2+. We screened various metal ions and discovered specific metal ions augmented STING agonist activity, wherein Mn2+ promoted a 12- to 77-fold potentiation effect across the prevalent human STING haplotypes. Notably, Mn2+ coordinated with CDN STING agonists to self-assemble into a nanoparticle (CDN-Mn2+ particle, CMP) that effectively delivered STING agonists to immune cells. The CMP, administered either by local intratumoural or systemic intravenous injection, initiated robust anti-tumour immunity, achieving remarkable therapeutic efficacy with minute doses of STING agonists in multiple murine tumour models. Overall, the CMP offers a new platform for local and systemic cancer treatments, and this work underscores the great potential of coordination nanomedicine for metalloimmunotherapy.

Regulation of T Cell Responses by Ionic Salt Signals.

T helper cell responses are tailored to their respective antigens and adapted to their specific tissue microenvironment. While a great proportion of T cells acquire a resident identity, a significant proportion of T cells continue circulating, thus encountering changing microenvironmental signals during immune surveillance. One signal, which has previously been largely overlooked, is sodium chloride. It has been proposed to have potent effects on T cell responses in the context of autoimmune, allergic and infectious tissue inflammation in mouse models and humans. Sodium chloride is stringently regulated in the blood by the kidneys but displays differential deposition patterns in peripheral tissues. Sodium chloride accumulation might furthermore be regulated by dietary intake and thus by intentional behavior. Together, these results make sodium chloride an interesting but still controversial signal for immune modulation. Its downstream cellular activities represent a potential therapeutic target given its effects on T cell cytokine production. In this review article, we provide an overview and critical evaluation of the impact of this ionic signal on T helper cell polarization and T helper cell effector functions. In addition, the impact of sodium chloride from the tissue microenvironment is assessed for human health and disease and for its therapeutic potential.

Ionic protein-lipid interactions at the plasma membrane regulate the structure and function of immunoreceptors.

Adaptive lymphocytes express a panel of immunoreceptors on the cell surface. Phospholipids are the major components of cell membranes, but they have functional roles beyond forming lipid bilayers. In particular, acidic phospholipids forming microdomains in the plasma membrane can ionically interact with proteins via polybasic sequences, which can have functional consequences for the protein. We have shown that negatively charged acidic phospholipids can interact with positively charged juxtamembrane polybasic regions of immunoreceptors, such as TCR-CD3, CD28 and IgG-BCR, to regulate protein structure and function. Furthermore, we pay our attention to protein transmembrane domains. We show that a membrane-snorkeling Lys residue in integrin αLß2 regulates transmembrane heterodimer formation and integrin adhesion through ionic interplay with acidic phospholipids and calcium ions (Ca2+) in T cells, thus providing a new mechanism of integrin activation. Here, we review our recent progress showcasing the importance of both juxtamembrane and intramembrane ionic protein-lipid interactions.

Comparison of Inflammatory Cell-Induced Corrosion and Electrocautery-Induced Damage of Total Knee Implants.

Recently, inflammatory cell-induced corrosion (ICIC), a unique type of damage, has been reported in cobalt-chromium (CoCr) implants, but the mechanism remains poorly understood and controversial because electrocautery damage has also been shown to produce similar findings. This study aimed to distinguish between these two damage mechanisms. Forty-one CoCr primary total knee arthroplasty specimens were collected at time of necropsy. After removal and cleaning, light microscopy was used to identify areas of ICIC-like damage scars. A CoCr knee implant was intentionally damaged by electrocautery from both Bovie and Aquamantys sources using a 3-second hover method with 3 different energy settings for comparison to necropsy findings. Average roughness (Ra), max peak-to-valley height (Rmax), kurtosis (Rk), and skewness (Rsk) measurements were collected to represent the topography on the damaged areas for the CoCr implants. Necropsy implants showed signs of ICIC in 7 of 41 implants (17%) examined. Fe/C ratios of the Bovie electrocautery-damaged knee implant were shown to be statistically higher than those of necropsy-retrieved implants. Median Ra measurements were statistically less (P = 0.008) for Bovie-damaged areas compared to ICIC-dam-aged areas on CoCr. Median Rmax and Ra measurements were statistically less (P = 0.012, P < 0.001, respectively) for Aquamantys-damaged areas compared to ICIC-damaged areas on CoCr. While the visual patterns seen in necropsy-retrieved implants appeared similar to those with the intentionally damaged CoCrMo implant, the contents of the corroded regions are unique. The difference in roughness found on ICIC-damaged and electrocautery-damaged regions also indicates examination of surface topography as another distinguishing feature between the two mechanisms.

An Animal Model Using Metallic Ions to Produce Autoimmune Nephritis.

Autoimmune nephritis triggered by metallic ions was assessed in a Long-Evans rat model. The parameters evaluated included antinuclear autoantibody production, kidney damage mediated by immune complexes detected by immunofluorescence, and renal function tested by retention of nitrogen waste products and proteinuria. To accomplish our goal, the animals were treated with the following ionic metals: HgCl2, CuSO4, AgNO3, and Pb(NO3)2. A group without ionic metals was used as the control. The results of the present investigation demonstrated that metallic ions triggered antinuclear antibody production in 60% of animals, some of them with anti-DNA specificity. Furthermore, all animals treated with heavy metals developed toxic glomerulonephritis with immune complex deposition along the mesangium and membranes. These phenomena were accompanied by proteinuria and increased concentrations of urea. Based on these results, we conclude that metallic ions may induce experimental autoimmune nephritis.

Influence of metal ions on human lymphocytes and the generation of titanium-specific T-lymphocytes.

BACKGROUND: There is mounting evidence to suggest the involvement of the immune system by means of activation by metal ions released via biocorrosion, in the pathophysiologic mechanisms of aseptic loosening of orthopedic implants. However, the detailed mechanisms of how metal ions become antigenic and are presented to T-lymphocytes, in addition to how the local inflammatory response is driven, remain to be investigated. METHODS: Human T-lymphocytes were cultured in the presence of a variety of metal ions before investigating functional and phenotypic changes using flow cytometric analysis. Additionally, human monocyte-derived dendritic cells (mDC) loaded with metal ions were used as antigen-presenting cells and incubated with naive T-lymphocytes with the aim of generating titanium-specific T-lymphocytes. RESULTS: Using an autologous in vitro model, with mDC treated with Titanium (IV), we were able to induce Titanium (IV)-specific T-lymphocytes. These T-lymphocytes responded in a dose-related manner to Titanium (IV), while they did not cross-react with Titanium (III) or other metal ions, indicating that the new antigenic peptide complexes formed by Titanium (IV) are highly specific. CONCLUSION: This study showed that mDC exposed to Titanium (IV) are able to induce the generation of Titanium (IV)-specific T-lymphocytes, demonstrating the strong and specific antigenicity of Titanium (IV) ions released by biocorrosion.

[Preclinical evaluation of coated knee implants for allergic patients]. / Präklinische Ergebnisse beschichteter Knieimplantate für Allergiker.

BACKGROUND: 10-15% of the population show allergic reactions against skin contact to metals as nickel, cobalt or chromium and have thus a risk of not tolerating implants containing those materials. The relationship between periimplantary hypersensivity reaction and given cutaneous contact allergy is currently unknown. A new developed multilayer coating system is supposed to prevent long-term allergic reactions that may result from uncoated implants. METHODS: Stability and function (concerning bonding durability, wear and ion release to the serum) of the multilayer coating system has been examined in a test series. RESULTS: The specific architecture of the multilayer coating system evidences a very good bonding durability. The results of the test in the simulator show a reduction of wear of approximately 60% compared to the uncoated implants. Ion concentrations within the serum of the wear tests were by magnitudes lower than those measured in reference tests on uncoated components. CONCLUSION: The results of the preclinical evaluation prove that the durability and function of the multilayer coating system are as intended.

[Hypersensitivity to metals in patients with orthopedic implants]. / Hipersensibilidad a metales en pacientes con implantes ortopédicos.

All metals in contact with biological systems suffer corrosion, which is an electrochemical process that causes metallic ions formation, known as haptens, which link with endogenous or exogenous proteins, therefore inducing an immune response. A hypersensitivity response to an implanted material should be suspected when cutaneous lesions or inflammatory reactions occur proximal to or surrounding the site of the metallic orthopedic implant. At present there is no a reliable diagnostic test for the determination of hypersensitivity to implanted metallic devices. It has been shown that the products of corrosive degradation are associated with dermatitis, urticaria and vasculitis. Cutaneous lesions in patients with unsuccessful metallic implants are more frequent than in non-rejected implants or the general population. Although the cellular and humoral hypersensitivity response in metallic orthopedic implants has been clearly identified, the risk is very low. Nowadays the importance of hypersensitivity to metals as a contributing factor in the failure of implants is unknown.

Unconventional roles of the NADPH oxidase: signaling, ion homeostasis, and cell death.

Although the central role of the phagocytic NADPH oxidase in mediating bacterial killing has long been appreciated, this sophisticated enzyme complex serves various other important functions. This Perspective focuses on these underappreciated roles of phagocytic NADPH oxidase, highlighting recent work implicating reactive oxygen species in triggering an unconventional form of cell death.

Interactions of chemicals and metal ions with proteins and role for immune responses.

Chemicals and metal ions often induce allergic contact dermatitis. We review here recent advances in the development of in vitro assays for prediction of skin sensitizing potency based on chemical and biological reactivity as well as in the identification of physiological binding partners and immunological pathomechanisms of chemical and metal ion induced disease.

c-Jun N-terminal kinase is involved in mercuric ions-mediated interleukin-4 secretion in mast cells.

BACKGROUND: Interleukin (IL)-4 plays a prominent role in immune response. Mercuric compounds upregulate IL-4 expression in animal tissues, and this upregulation plays a role in mercuric-mediated immunomodulation. Mercuric ions-mediated IL-4 expression was observed in vitro in T lymphocytes and mast cells. In the present study, we investigated molecular mechanisms responsible for this effect of mercuric ions in mast cells. METHODS: C1.MC/C57.1 mouse mast cells were exposed in vitro to increasing concentrations of Hg(2+) in the absence or presence of the specific c-Jun N-terminal kinase (JNK) inhibitor SP600125. The level of phosphorylated c-Jun in mast cells was determined by Western blotting, JNK activity assessed with in vitro kinase assay and the amount of secreted IL-4 determined by ELISA. RESULTS: We observed that Hg(2+) upregulated c-Jun phosphorylation on Ser 73 at concentrations which overlapped concentrations mediating IL-4 secretion. Phosphorylation of c-Jun in mast cells was associated with an increase in JNK activity. The specific JNK inhibitor SP600125 abolished both mercuric-induced c-Jun phosphorylation and IL-4 secretion in mast cells. CONCLUSIONS: These observations are consistent with the hypothesis that JNK is one of the signaling proteins mediating the effect of Hg(2+) on IL-4 expression in mast cells and is engaged in environmentally mediated immunomodulation.

T lymphocyte-mediated immune responses to chemical haptens and metal ions: implications for allergic and autoimmune disease.

Chemical haptens and metal ions interact with proteins and thereby become recognizable by T and B lymphocytes. They induce the production of proinflammatory cytokines and chemokines by various cell types due to triggering of innate immune responses. This is an important prerequisite for the activation of the adaptive immune system and the development of diseases like allergic contact dermatitis and adverse drug and autoimmune reactions. Our increasing knowledge about the molecular basis of hapten and metal ion recognition by T cells and about the pathomechanisms of contact hypersensitivity and chemical-induced autoimmune reactions allows concomitant progress in the development of modern strategies for immunotherapy and will hopefully enable more specific intervention in hapten- and metal ion-induced human diseases in the future.