Platelet Membrane-Camouflaged Nanoparticles Carry microRNA inhibitor Against Myocardial Ischemia-Reperfusion Injury

Background The incidence of myocardial ischemia reperfusion injury (MIRI) is increasing year by year, and there is an urgent need to develop new treatment methods. Nrf2 is believed to play a protective role during MIRI and is regulated by microRNAs (miRNAs). Platelets are physiologically targeted to MIRI injury sites. The focus of this study is on platelet membranes, also called platelet membrane vesicles (PMVs), camouflaged PLGA nanoparticles, carrying microRNA inhibitors to regulate Nrf2, and play a therapeutic role during MIRI. Results First, we characterized the high transfection efficiency and low toxicity of PLGA in vitro, as well as the good targeting of PMVs in vivo; then, we found a microRNA (microRNA-155-5p) that effectively regulates Nrf2 in vitro, and confirmed its effect on cardiomyocyte apoptosis during MIRI; finally, PMVs camouflaged PLGA-miRNA complexes (PMVs@PLGA-miRNA complexes) were prepared and applied to MIRI treatment, and it was found that it can significantly alleviate the myocardial damage caused by MIRI in vivo and exert effective therapeutic effects. Conclusions This research has developed a PMVs camouflaged PLGA nanoparticles, which can carry microRNA inhibitors (PMVs@PLGA-miRNA complexes), which can be targeted and efficiently transfected into cardiomyocytes, and play an important role in the treatment of MIRI. Our results suggest a novel biological delivery system that targets M​​IRI.

Morphofunctional assessment of platelet activity correction in hyperbaric blood oxygenation

100 patients with functional class II-III exertional angina were examined. The subjects underwent a 10-day course of hyperbaric oxygenation (HBO) in the 1.2 ATA mode for 40 minutes, against the background of standard therapy for coronary heart disease (IHD). Before and after HBO, the platelet link of hemostasis and the elastic properties of the platelet membrane were assessed. Assessment of the effect of the HBO course on the functional state of platelets, depending on their aggregation activity, showed that in patients with initially normal platelet aggregation, there is a tendency to a decrease in spontaneous aggregation, in contrast to patients with initial hypoaggregation, HBO promoted a significant increase in spontaneous aggregation. The use of a 10-day course of HBO was accompanied by a reaction of reducing the elasticity of the platelet biomembrane. Key words: aggregation; atomic force microscopy; platelet membrane; hyperbaric oxygenation.

A novel biomimetic nanomedicine system with anti-inflammatory and anti-osteoporosis effects improves the therapy efficacy of steroid-resistant nephrotic syndrome

Clinically, steroid-resistant nephrotic syndrome (SRNS) is always prolonged and difficult to treat and easily develops into end-stage renal disease, resulting in a low survival rate. Strategies to reverse steroid resistance and reduce the long-term use of high doses of steroid medicines are urgently needed. In this study, a novel nanoparticle drug system (Pm-GCH) with a core–shell structure was designed. Metal–organic frameworks, synthesized by glycyrrhizic acid (G) and calcium ions (Ca2+) loaded with hydrocortisone (H) were the core of the nanoparticles. Platelet membrane vesicles were the shells. The natural platelet membrane endows Pm-GCH with good biocompatibility and the ability to promote immune escape. In addition, under the chemotaxis of inflammatory factors, platelet membranes assist Pm-GCH in nonspecific targeting of the inflammatory sites of the kidney. Under an inflammatory acid environment, GCH slowly degrades and releases glycyrrhizic acid and hydrocortisone. Glycyrrhizic acid inhibits the inactivation of hydrocortisone, jointly inhibits the activity of phospholipase A2 (PLA2) and the classic activation pathway of complement C2, blocks the production of inflammatory factors, plays an anti-inflammatory role, and enhances the efficacy of hydrocortisone in the treatment of SRNS. Moreover, glycyrrhizic acid alleviates osteoporosis induced by long-term use of glucocorticoids. These results indicate that Pm-GCH is a promising treatment strategy for SRNS. Graphical Abstract

Integrated endotoxin-adsorption and antibacterial properties of platelet-membrane-coated copper silicate hollow microspheres for wound healing

Serious infection caused by drug-resistant gram-negative bacteria and their secreted toxins (e.g., lipopolysaccharide) is a serious threat to human health. Thus, treatment strategies that efficiently kill bacteria and reducing the impact of their toxins simultaneously are urgently required. Herein, a novel antibacterial platform composed of a mesoporous copper silicate microsphere (CSO) core and a platelet membrane (PM) shell was prepared (CSO@PM). CSO@PM specifically targets bacteria owing to formyl peptide receptors on the PM and, combined with photothermal therapy (PTT), exhibits highly effective bacter icidal activity. Importantly, CSO@PM can adsorb lipopolysaccharide secreted by gram-negative bacteria, resulting in inflammation reduction. Thus, CSO@PM stimulates re-epithelialization and granulation-tissue formation, promoting wound healing. Moreover, this antibacterial platform exhibits no obvious toxicity at all the test concentrations in vitro and in vivo. Thus, CSO@PM exhibits a robust antibacterial effect and a strong toxin-adsorption capacity, facilitating the clinical treatment of many bacterial infections and the development of next-generation antibacterial nanoagents. Graphical Abstract

Genetic Removal of Terminal Sialic Acid Residues from the O-Linked Glycans Adjacent to the HPA-9b Polymorphism of Platelet Membrane Glycoprotein IIb Improves the Binding and Detection of HPA-9b Patient Alloantibodies

Sialic acids occupy the terminal position of glycan chains, and have the potential to influence the antigenicity of glycoproteins. Antibody binding sites on a glycoprotein can be solely protein in nature, or can include or be affected by nearby glycan chains, which may either mask the epitope, or conversely comprise part of the antibody binding site. The polymorphisms responsible for formation of the Human Platelet Alloantigens (HPA)-3 (Ile843Ser) and HPA-9 (Val837Met) are next to each other near the C-terminus of the extracellular domain of platelet membrane glycoprotein (GP)IIb, and are adjacent to sialyl-Core 1 O-glycans that emanate from serines 845 and 847. Previous studies have shown that these O-linked glycans are required to support the binding of some of HPA-3a alloantibodies. Loss of these glycans, especially terminal sialic acid residues, during platelet storage or preparation, can present major difficulties in detecting clinically important anti-HPA-3a alloantibodies in suspected cases of fetal/neonatal alloimmune thrombocytopenia (FNAIT). Similarly, detection and identification of anti-HPA-9b alloantibodies from FNAIT patient sera can also be extremely challenging, resulting in the inability to resolve clinical cases of this bleeding disorder. Whether the nearby O-glycans on serines 845 and 847 of GPIIb affect the antigenicity of HPA-9b, and/or influence the binding of anti-HPA-9b alloantibodies in clinically significant cases of FNAIT is unknown. We previously reported the generation of bioengineered, HLA class I-negative, HPA-9a or -9b allele-specific megakaryocytes (MKs) from human induced pluripotent stem cells (iPSCs) that are suitable for whole-cell flow cytometric detection of anti-HPA-9b alloantibodies (Blood 2019;134(22):e1-e8). Unexpectedly, treatment of these allele-specific MKs with neuraminidase actually enhanced the binding of anti-HPA-9b alloantibodies, suggesting that terminal sialic acids on GPIIb partially mask the HPA-9b epitope. To test the hypothesis that removal of terminal sialic acids on nearby O-glycans, or removal of the entire O-glycan chains emanating from Ser845/847 of GPIIb, might enhance the detection of anti-HPA-9b patient alloantibodies, we created a series of deletion mutants in two major sialidases, ST3GAL1 and ST3GAL2, known to be responsible for transferring terminal sialic acid residues to Core 1 O-glycans, in our HPA-9a and -9b allele-specific iPSCs. Immunoprecipitation/western blot analysis confirmed the complete removal of terminal sialic acids on the O-glycan chains of GPIIb in ST3GAL1/2 knockout (KO) iPSC-derived MKs, as reported by the binding of the lectin PNA to the exposed Core 1 structure on GPIIb. These sialylation-deficient ST3GAL1/2 KO HPA-9b MKs exhibited dramatically increased anti-HPA-9b alloantibody binding, further confirming the notion that HPA-9b epitopes are partially masked by terminal sialic acids on nearby GPIIb O-glycan chains. Finally, allele-specific iPSCs lacking the complete O-glycan chains attached to serines 845 and 847 of GPIIb were generated by mutating those residues to alanines using a similar CRISPR/Cas9 gene editing approach. Interestingly, O-glycan chain-deficient Ala845/847 mutant MKs carrying the HPA-9b polymorphism exhibited slightly to moderately reduced binding of anti-HPA-9b alloantibodies, indicating that the presence of the Core 1 O-glycan chains attached to GPIIb serine residues 845 and 847 contribute to the presentation of the HPA-9b epitope - perhaps by stabilizing the conformation of the glycoprotein in this region. Taken together, these data suggest that detection of anti-HPA-9b alloantibodies may be enhanced through the use of iPSC-derived HPA-9b-specific MKs that have been genetically altered to lack nearby terminal sialic acid residues, but retain the glycan chains to which they are attached. Disclosures Curtis: Rallybio: Consultancy. Newman: Rallybio: Consultancy, Research Funding.

Construction of Nano-Carriers Coated with Platelet Membrane and Its Application in Targeted Therapy of Inflammation

In this study, poly (lactic acid-glycolic acid) (PLGA) nanoparticles loaded with anti-inflammatory drug ketoprofen (KET) were prepared and then coated with platelet membrane (PLTM) to form KET@PLTM-PLGA nano-particles (NPs). The particle size of the KET@PLTM-PLGA NPs is 176[Formula: see text]nm and the surface protein is the same as that of PLTM. The results of confocal microscopy and flow cytometry showed that the KET@PLTM-PLGA NPs uptake of RAW264.7 induced by LPS was significantly higher than that of KET@PLGA NPs, without PLTM, which was due to the binding of P-selectin to CD44 receptors on the surface of RAW264.7 cells induced by LPS on the surface of PLTM. Compared with other KET preparations, KET@PLTM-PLGA NPs have better anti-inflammatory effect.

Integrated Endotoxin-Adsorption and Antibacterial Properties of Platelet-Membrane-Coated Copper Silicate Hollow Microspheres for Wound Healing

Serious infection caused by drug-resistant gram-negative bacteria and their secreted toxins (e.g., lipopolysaccharide) is a serious threat to human health. Thus, treatment strategies that efficiently kill bacteria and reducing the impact of their toxins simultaneously are urgently required. Herein, a novel antibacterial platform composed of a mesoporous copper silicate microsphere (CSO) core and a platelet membrane (PM) shell was prepared (CSO@PM). CSO@PM specifically targets bacteria owing to formyl peptide receptors on the PM and, combined with photothermal therapy (PTT), exhibits highly effective bactericidal activity. Importantly, CSO@PM can adsorb lipopolysaccharide secreted by gram-negative bacteria, resulting in inflammation reduction. Thus, CSO@PM stimulates re-epithelialization and granulation-tissue formation, promoting wound healing. Moreover, this antibacterial platform exhibits no obvious toxicity at all the test concentrations in vitro and in vivo. Thus, CSO@PM exhibits a robust antibacterial effect and a strong toxin-adsorption capacity, facilitating the clinical treatment of many bacterial infections and the development of next-generation antibacterial nanoagents.