Cargo-free particles divert neutrophil-platelet aggregates to reduce thromboinflammation.

The combination of inflammation and thrombosis is a hallmark of many cardiovascular diseases. Under such conditions, platelets are recruited to an area of inflammation by forming platelet-leukocyte aggregates via interaction of PSGL-1 on leukocytes and P-selectin on activated platelets, which can bind to the endothelium. While particulate drug carriers have been utilized to passively redirect leukocytes from areas of inflammation, the downstream impact of these carriers on platelet accumulation in thromboinflammatory conditions has yet to be studied. Here, we explore the ability of polymeric particles to divert platelets away from inflamed blood vessels both in vitro and in vivo. We find that untargeted and targeted micron-sized polymeric particles can successfully reduce platelet adhesion to an inflamed endothelial monolayer in vitro in blood flow systems and in vivo in a lipopolysaccharide-induced, systemic inflammation murine model. Our data represent initial work in developing cargo-free, anti-platelet therapeutics specifically for conditions of thromboinflammation.

Polymeric particle-based therapies for acute inflammatory diseases.

Acute inflammation is essential for initiating and coordinating the body's response to injuries and infections. However, in acute inflammatory diseases, inflammation is not resolved but propagates further, which can ultimately lead to tissue damage such as in sepsis, acute respiratory distress syndrome and deep vein thrombosis. Currently, clinical protocols are limited to systemic steroidal treatments, fluids and antibiotics that focus on eradicating inflammation rather than modulating it. Strategies based on stem cell therapeutics and selective blocking of inflammatory molecules, despite showing great promise, still lack the scalability and specificity required to treat acute inflammation. By contrast, polymeric particle systems benefit from uniform manufacturing at large scales while preserving biocompatibility and versatility, thus providing an ideal platform for immune modulation. Here, we outline design aspects of polymeric particles including material, size, shape, deformability and surface modifications, providing a strategy for optimizing the targeting of acute inflammation.

Polysalicylic Acid Polymer Microparticle Decoys Therapeutically Treat Acute Respiratory Distress Syndrome.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) remain problematic due to high mortality rates and lack of effective treatments. Neutrophilic injury contributes to mortality in ALI/ARDS. Here, technology for rapid ARDS intervention is developed and evaluated, where intravenous salicylic acid-based polymer microparticles, i.e., Poly-Aspirin (Poly-A), interfere with neutrophils in blood, reducing lung neutrophil infiltration and injury in vivo in mouse models of ALI/ARDS. Importantly, Poly-A particles reduce multiple inflammatory cytokines in the airway and bacterial load in the bloodstream in a live bacteria lung infection model of ARDS, drastically improving survival. It is observed that phagocytosis of the Poly-A microparticles, with salicylic acid in the polymer backbone, alters the neutrophil surface expression of adhesion molecules, potentially contributing to their added therapeutic benefits. Given the proven safety profile of the microparticle degradation products-salicylic acid and adipic acid-it is anticipated that the Poly-A particles represent a therapeutic strategy in ARDS with a rare opportunity for rapid clinical translation.

Biodegradable, bile salt microparticles for localized fat dissolution.

Bile acids are proposed as therapeutic agents for various diseases, including liver diseases and obesity. However, oral or subcutaneous administration of a solubilized version of these drugs has limited efficacy and imposes unwanted side effects. Here, we describe a gold-templating method for fabricating stable, bile salt-cholate or deoxycholate-microparticles. The gold ions' reduction at the oil-water interface in a double emulsion solvent evaporation process enables a gold-bile salt interaction and the formation of bile salt particles. We demonstrate that composite microparticles release cholate/deoxycholate into solution via a surface erosion process. We illustrate these particles' capability to lyse adipocytes, both in vitro and in vivo, with minimal side effects, contrary to the Food and Drug Administration-approved salt solution that leads to severe inflammation and ulceration. Overall, particle-based cholate/deoxycholate opens opportunities for localized delivery of these salts, improving efficacy while minimizing side effects associated with oral and subcutaneous use.

Identification of putative effectors of the Type IV secretion system from the Wolbachia endosymbiont of Brugia malayi.

Wolbachia is an unculturable, intracellular bacterium that persists within an extremely broad range of arthropod and parasitic nematode hosts, where it is transmitted maternally to offspring via vertical transmission. In the filarial nematode Brugia malayi, a causative agent of human lymphatic filariasis, Wolbachia is an endosymbiont, and its presence is essential for proper nematode development, survival, and pathogenesis. While the elucidation of Wolbachia:nematode interactions that promote the bacterium's intracellular persistence is of great importance, research has been hampered due to the fact that Wolbachia cannot be cultured in the absence of host cells. The Wolbachia endosymbiont of B. malayi (wBm) has an active Type IV secretion system (T4SS). Here, we have screened 47 putative T4SS effector proteins of wBm for their ability to modulate growth or the cell biology of a typical eukaryotic cell, Saccharomyces cerevisiae. Five candidates strongly inhibited yeast growth upon expression, and 6 additional proteins showed toxicity in the presence of zinc and caffeine. Studies on the uptake of an endocytic vacuole-specific fluorescent marker, FM4-64, identified 4 proteins (wBm0076 wBm00114, wBm0447 and wBm0152) involved in vacuole membrane dynamics. The WAS(p)-family protein, wBm0076, was found to colocalize with yeast cortical actin patches and disrupted actin cytoskeleton dynamics upon expression. Deletion of the Arp2/3-activating protein, Abp1p, provided resistance to wBm0076 expression, suggesting a role for wBm0076 in regulating eukaryotic actin dynamics and cortical actin patch formation. Furthermore, wBm0152 was found to strongly disrupt endosome:vacuole cargo trafficking in yeast. This study provides molecular insight into the potential role of the T4SS in the Wolbachia endosymbiont:nematode relationship.