Endothelial cells are constantly exposed to environmental stress factors that, above a certain threshold, trigger cellular senescence and apoptosis. The altered vascular function affects new vessel formation and endothelial fitness, contributing to the progression of age-related diseases. This narrative review highlights the complex interplay between senescence, oxidative stress, extracellular vesicles, and the extracellular matrix and emphasizes the crucial role of angiogenesis in aging and Alzheimer’s disease. The interaction between the vascular and nervous systems is essential for the development of a healthy brain, especially since neurons are exceptionally dependent on nutrients carried by the blood. Therefore, anomalies in the delicate balance between pro- and antiangiogenic factors and the consequences of disrupted angiogenesis, such as misalignment, vascular leakage and disturbed blood flow, are responsible for neurodegeneration. The implications of altered non-productive angiogenesis in Alzheimer’s disease due to dysregulated Delta-Notch and VEGF signaling are further explored. Additionally, potential therapeutic strategies such as exercise and caloric restriction to modulate angiogenesis and vascular aging and to mitigate the associated debilitating symptoms are discussed. Moreover, both the roles of extracellular vesicles in stress-induced senescence and as an early detection marker for Alzheimer’s disease are considered. The intricate relationship between endothelial senescence and angiogenesis provides valuable insights into the mechanisms underlying angiogenesis-related disorders and opens avenues for future research and therapeutic interventions.

Rab GTPases control trafficking of intracellular vesicles and are key regulators of endocytic and secretory pathways. Due to their specific distribution, they may serve as markers for different endolysosomal compartments. Since Rab GTPases are involved in uptake and trafficking of endocytosed ligands and cell receptors, as well as secretion of immune mediators, they have been implicated in diverse immunological processes and their functions are often exploited by intracellular pathogens such as viruses. While Rab proteins have been studied extensively in mammals, their functions in vesicle trafficking in teleosts are not well known. In the present work, Atlantic salmon Rab5c, Rab7a and Rab27a homologs were studied in terms of intracellular distribution and gene expression. Structured illumination microscopy demonstrated that transgenic, GFP-tagged salmon Rab5c and Rab7a are, predominantly, located within early endosomes and late endosomes/lysosomes, respectively. In contrast, Rab27a showed a broader distribution, which indicates that it associates with diverse intracellular vesicles and organelles. Infection of salmon with Salmonid alphavirus subtype 3 (SAV3) enhanced the mRNA levels of all of the studied Rab isoforms in heart and head kidney and most of them were upregulated in spleen. This may reflect the capacity of the virus to exploit the functions of these rab proteins. It is also possible that the transcriptional regulation of Rab proteins in SAV3-infected organs may play a role in the antiviral immune response. The latter was further supported by in vitro experiments with adherent head kidney leukocytes. The expression of Rab5c and Rab27a was upregulated in these cells following stimulation with TLR ligands including CpG oligonucleotides and polyl:C. The expression of most of the analyzed Rab isoforms in the primary leukocytes was also enhanced by stimulation with type I IFN. Interestingly, IFN-gamma had a negative effect on Rab7a expression which may be linked to the priming activity of this cytokine on monocytes and macrophages. Overall, these data demonstrate that the intracellular distribution of Rab5c, Rab7a and Rab27a is phylogenetically conserved within vertebrates and that these molecules might be implicated in viral infections and the regulation of the antiviral immune response in Atlantic salmon.

β‐Glucans (BG) are glucose polymers which are produced in bacteria and fungi but not in vertebrate organisms. Being recognized by phagocytic leukocytes including macrophages and neutrophils through receptors such as dectin-1 and Complement receptor 3 (CR3), the BG are perceived by the innate immune system of vertebrates as foreign substances known as Pathogen Associated Molecular Patterns (PAMPs). The yeast-derived BG has been recognized for its potent biological activity and it is used as an immunomodulator in human and veterinary medicine. The goal of the current study was to characterize the immunostimulatory activity of soluble yeast BG in primary cultures of Atlantic salmon (Salmo salar) head kidney leukocytes (HKLs) in which phagocytic cell types including neutrophils and mononuclear phagocytes predominate. The effect of BG on the secretome of HKL cultures, including secretion of extracellular vesicles (EVs) and soluble protein55s was characterized through western blotting and mass spectrometry. The results demonstrate that, along with upregulation of proinflammatory genes, BG induces secretion of ubiquitinated proteins (UbP), MHCII-containing EVs from professional antigen presenting cells as well as proteins derived from granules of polymorphonuclear granulocytes (PMN). Among the most abundant proteins identified in BG-induced EVs were beta-2 integrin subunits, including CD18 and CD11 homologs, which highlights the role of salmon granulocytes and mononuclear phagocytes in the response to soluble BG. Overall, the current work advances the knowledge about the immunostimulatory activity of yeast BG on the salmon immune system by shedding light on the effect of this PAMP on the secretome of salmon leukocytes.

Nanotechnology offers alternative approaches to the discovery of anticancer drugs. Hydrophobic bioactive components can be included in the cores of amphiphilic nanocarriers, which leads to the formation of a water-dispersible product with improved bioavailability, facilitated excretion, and reduced systemic toxicity in the treated organisms. This study was aimed at the formation of polymer nanocarriers, loaded with anticancer drug precursor podophylotoxin (PPT) or PPT-containing juniper leaf extracts, seeking to study their antineoplastic activity in A-431 epidermoid carcinoma cells and HaCaT normal keratinocytes. The amphiphilic, biodegradable, and biocompatible MPEG-b-PLA diblock copolymer was self-assembled in aqueous media into nanosized particles, whose physicochemical characteristics were studied by dynamic light scattering, transmission electron microscopy, and other methods. High encapsulation efficiency was determined for the PPT component-loaded micelles. DNA fragmentation, cell cycle arrest, nuclear condensation, membrane lipid order assessment, reactive oxygen species, and apoptosis induction by the loaded nanocarriers in A-431 or HaCaT cells were analyzed by the comet assay, FACS, Hoechst DNA staining, Laurdan generalized polarization, and other methods. As a result of various cellular processes induced by the PPT component-loaded nanoparticles, effector caspase-3 and caspase-7 activation showed selectivity towards tumor cells compared to the normal cells. The newly obtained PPT-containing nanoparticles have applications as potential drugs in the prospective nanomedicine.

Extracellular vesicles (EVs) secreted by glioblastoma multiforme and other types of cancer cells are key factors contributing to the aggressiveness of the disease and its resistance to therapy. Chloroquine (CHQ), a lysosomal inhibitor, has shown potential as an enhancer of temozolomide (TMZ) cytotoxicity against glioblastoma cells. Since both CHQ and TMZ are known to modulate EV secretion, we sought to investigate their potential interplay in this process. Simultaneous treatment of TMZ-sensitive (U87-MG) and TMZ-resistant (U138-MG) glioblastoma cells with TMZ and CHQ led to a synergistic upregulation of EV secretion. Although CHQ did not enhance the TMZ cytotoxicity in U87-MG cells, it synergized with the latter to upregulate the release of extracellular nucleic acids implicating activation of unconventional secretory pathways. Synergistic upregulation of the autophagy markers LC3B-II and p62 by CHQ and TMZ in both cells and EVs indicates secretory autophagy is likely involved in the observed unconventional secretion. Moreover, a significant enrichment of caveolin-1 in small EVs highlights their potential role in modulating tumor aggressiveness. The synergy in EV upregulation was not confined to the specific biological activity of TMZ and CHQ; similar effects were observed upon co-treatments with CHQ and etoposide (a topoisomerase inhibitor) and TMZ and Bafilomycin A1 (another lysosomal inhibitor). Heightened EV release was also observed in THP-1 monocytes and macrophages treated with Bafilomycin and TMZ, highlighting a broader, cell type-independent mechanism. These findings indicate that combined DNA damage and lysosomal inhibition synergistically stimulate secretory autophagy and EV release, potentially impacting the tumor microenvironment and driving disease progression.

Extracellular vesicles (EVs) secreted by glioblastoma multiforme and other types of cancer cells are key factors contributing to the aggressiveness of the disease and its resistance to therapy. Chloroquine (CHQ), a lysosomal inhibitor, has shown potential as an enhancer of temozolomide (TMZ) cytotoxicity against glioblastoma cells. Since both CHQ and TMZ are known to modulate EV secretion, we sought to investigate their potential interplay in this process. Simultaneous treatment of TMZ-sensitive (U87-MG) and TMZ-resistant (U138-MG) glioblastoma cells with TMZ and CHQ led to a synergistic upregulation of EV secretion. Although CHQ did not enhance the TMZ cytotoxicity in U87-MG cells, it synergized with the latter to upregulate the release of extracellular nucleic acids implicating activation of unconventional secretory pathways. Synergistic upregulation of the autophagy markers LC3B-II and p62 by CHQ and TMZ in both cells and EVs indicates that secretory autophagy is likely involved in the observed unconventional secretion. Moreover, a significant enrichment of caveolin-1 in small EVs highlights their potential role in modulating tumor aggressiveness. The synergy in EV upregulation was not confined to the specific biological activity of TMZ and CHQ; similar effects were observed upon co-treatments with CHQ and etoposide (a topoisomerase inhibitor) and TMZ and Bafilomycin A1 (another lysosomal inhibitor). Heightened EV release was also observed in THP-1 monocytes and macrophages treated with Bafilomycin and TMZ, highlighting a broader, cell-type-independent mechanism. These findings indicate that combined DNA damage and lysosomal inhibition synergistically stimulate secretory autophagy and EV release, potentially impacting the tumor microenvironment and driving disease progression.