Tetranuclear Polypyridylruthenium(II) Complexes as Selective Nucleic Acid Stains for Flow Cytometric Analysis of Monocytic and Epithelial Lung Carcinoma Large Extracellular Vesicles

• Published in: Biomolecules (Basel, Switzerland) Vol. 14; no. 6; p. 664
• Main Authors: Wardhani, Kartika, Levina, Aviva, Sun, Biyun, Zou, Haipei, Grau, Georges E R, Keene, F Richard, Collins, J Grant, Lay, Peter A
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 06.06.2024; MDPI
• Subjects: A549 Cells; Acids; Bacterial infections; BASIC BIOLOGICAL SCIENCES; Biological Science; Cancer; Carcinoma; Cell culture; Cell differentiation; Cell Line, Tumor; Cell membranes; Coordination Complexes - chemistry; Coordination Complexes - pharmacology; Extracellular vesicles; Extracellular Vesicles - metabolism; Flow cytometry; Flow Cytometry - methods; Health aspects; Humans; Immune system; Immunotherapy; Inorganic and Physical Chemistry; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Labeling; Leukemia; Lipids; Lipopolysaccharides; Lipopolysaccharides - pharmacology; Lung cancer; Lung carcinoma; Lung Neoplasms - metabolism; Lung Neoplasms - pathology; Medical research; Medicine, Experimental; microvesicles; Monocytes; Monocytes - metabolism; Monocytic leukemia; nucleic acids; Nucleic Acids - metabolism; Phosphorescence; Physiology; Proteins; Quantum dots; RNA; Roles; ruthenium phosphorescent complexes; Scientific equipment and supplies industry; selective extracellular vesicle stain; Staining and Labeling - methods; Stains; Stains & staining; Therapeutic applications; THP-1 Cells; Australia; United States; United States > US; Germany; selective extracellular vesicle stain; flow cytometry; microvesicles; nucleic acids; ruthenium phosphorescent complexes
• ISSN: 2218-273X; 2218-273X
• DOI: 10.3390/biom14060664

Selective staining of extracellular vesicles (EVs) is a major challenge for diagnostic and therapeutic applications. Herein, the EV labeling properties of a new class of tetranuclear polypyridylruthenium(II) complexes, Rubb -TNL and Rubb -TL, as phosphorescent stains are described. These new stains have many advantages over standard stains to detect and characterize EVs, including: high specificity for EV staining versus cell staining; high phosphorescence yields; photostability; and a lack of leaching from EVs until incorporation with target cells. As an example of their utility, large EVs released from control (basal) or lipopolysaccharide (LPS)-stimulated THP-1 monocytic leukemia cells were studied as a model of immune system EVs released during bacterial infection. Key findings from EV staining combined with flow cytometry were as follows: (i) LPS-stimulated THP-1 cells generated significantly larger and more numerous large EVs, as compared with those from unstimulated cells; (ii) EVs retained native EV physical properties after staining; and (iii) the new stains selectively differentiated intact large EVs from artificial liposomes, which are models of cell membrane fragments or other lipid-containing debris, as well as distinguished two distinct subpopulations of monocytic EVs within the same experiment, as a result of biochemical differences between unstimulated and LPS-stimulated monocytes. Comparatively, the staining patterns of A549 epithelial lung carcinoma-derived EVs closely resembled those of THP-1 cell line-derived EVs, which highlighted similarities in their selective staining despite their distinct cellular origins. This is consistent with the hypothesis that these new phosphorescent stains target RNA within the EVs.