Nanocarriers for natural polyphenol senotherapeutics.

Senescence is a heterogenous and dynamic process in which various cell types undergo cell-cycle arrest due to cellular stressors. While senescence has been implicated in aging and many human pathologies, therapeutic interventions remain inadequate due to the absence of a comprehensive set of biomarkers in a context-dependent manner. Polyphenols have been investigated as senotherapeutics in both preclinical and clinical settings. However, their use is hindered by limited stability, toxicity, modest bioavailability, and often inadequate concentration at target sites. To address these limitations, nanocarriers such as polymer nanoparticles and lipid vesicles can be utilized to enhance the efficacy of senolytic polyphenols. Focusing on widely studied senolytic agents-specifically fisetin, quercetin, and resveratrol-we provide concise summaries of their physical and chemical properties, along with an overview of preclinical and clinical findings. We also highlight common signaling pathways and potential toxicities associated with these agents. Addressing challenges linked to nanocarriers, we present examples of senotherapeutic delivery to various cell types, both with and without nanocarriers. Finally, continued research and development of senolytic agents and nanocarriers are encouraged to reduce the undesirable effects of senescence on different cell types and organs. This review underscores the need for establishing reliable sets of senescence biomarkers that could assist in evaluating the effectiveness of current and future senotherapeutic candidates and nanocarriers.

Modulation of Abundance and Location of High-Mobility Group Box 1 in Human Microglia and Macrophages under Oxygen-Glucose Deprivation.

While stroke represents one of the main causes of death worldwide, available effective drug treatment options remain limited to classic thrombolysis with recombinant tissue plasminogen activator (rtPA) for arterial-clot occlusion. Following stroke, multiple pathways become engaged in producing a vicious proinflammatory cycle through the release of damage-associated molecular patterns (DAMPs) such as high-mobility group box 1 (HMGB1) and heat shock protein 70 kDa (HSP72). HMGB1, in particular, can activate proinflammatory cytokine production when acetylated (AcHMGB1), a form that prefers cytosolic localization and extracellular release. This study aimed at determining how HMGB1 and HSP72 are modulated and affected following treatment with the anti-inflammatory compound resveratrol and novel platelet membrane-derived nanocarriers loaded with rtPA (CSM@rtPA) recently developed by our group for ischemic artery recanalization. Under ischemic conditions of oxygen-glucose deprivation (OGD), nuclear abundance of HMGB1 and AcHMGB1 in microglia and macrophages decreased, whereas treatment with CSM@rtPA did not alter nuclear or cytosolic abundance. Resveratrol treatment markedly increased the cytosolic abundance of HSP72 in microglia. Using proximity ligation assays, we determined that HSP72 interacted with HMGB1 and with acetylated HMGB1. The interaction was differentially affected under the OGD conditions. Resveratrol treatment under the OGD further decreased HSP72-HMGB1 interactions, whereas, in contrast, treatment increased HSP72-AcHMGB1 interactions in microglia. This study points out a salient molecular interaction suited for a two-pronged nanotherapeutic intervention in stroke: enhancement of rtPA's thrombolytic activity and modulation of cytosolic interactions between HMGB1 and HSP72 by resveratrol.

Thrombolytic therapy based on lyophilized platelet-derived nanocarriers for ischemic stroke.

BACKGROUND: Intravenous administration of fibrinolytic drugs, such as recombinant tissue plasminogen activator (rtPA) is the standard treatment of acute thrombotic diseases. However, current fibrinolytics exhibit limited clinical efficacy because of their short plasma half-lives and risk of hemorrhagic transformations. Platelet membrane-based nanocarriers have received increasing attention for ischemic stroke therapies, as they have natural thrombus-targeting activity, can prolong half-life of the fibrinolytic therapy, and reduce side effects. In this study we have gone further in developing platelet-derived nanocarriers (defined as cellsomes) to encapsulate and protect rtPA from degradation. Following lyophilization and characterization, their formulation properties, biocompatibility, therapeutic effect, and risk of hemorrhages were later investigated in a thromboembolic model of stroke in mice. RESULTS: Cellsomes of 200 nm size and loaded with rtPA were generated from membrane fragments of human platelets. The lyophilization process did not influence the nanocarrier size distribution, morphology, and colloidal stability conferring particle preservation and long-term storage. Encapsulated rtPA in cellsomes and administered as a single bolus showed to be as effective as a continuous clinical perfusion of free rtPA at equal concentration, without increasing the risk of hemorrhagic transformations or provoking an inflammatory response. CONCLUSIONS: This study provides evidence for the safe and effective use of lyophilized biomimetic platelet-derived nanomedicine for precise thrombolytic treatment of acute ischemic stroke. In addition, this new nanoformulation could simplify the clinical use of rtPA as a single bolus, being easier and less time-consuming in an emergency setting than a treatment perfusion, particularly in stroke patients. We have successfully addressed one of the main barriers to drug application and commercialization, the long-term storage of nanomedicines, overcoming the potential chemical and physical instabilities of nanomedicines when stored in an aqueous buffer.