Assessment of Drug Activities against Giardia Using Hyperspectral Raman Microscopy

• Published in: Pathogens (Basel) Vol. 13; no. 5; p. 358
• Main Authors: Manciu, Felicia S, Guerrero, Jose, Pence, Breanna C, Martinez Lopez, Lizbeth V, Das, Siddhartha
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27-04-2024
• Subjects: Bile; Cellular structure; confocal fluorescence microscopy; Cysts; drug assessment; Drug resistance; Drugs; Fluorescence microscopy; Giardia; Giardiasis; Glycogen; Glycogens; Heme proteins; Immunology; Infections; Intermediates; Iron; Lipids; Metronidazole; Microscopy; Oseltamivir; Oxidative stress; Parasites; Pathogens; Phenylalanine; Phospholipids; Proteins; Protozoa; Raman microscopy; Small intestine; Spectrum analysis; Tropical diseases; St Louis Missouri; United States > US; non-tagged analytes; Raman microscopy; giardiasis; confocal fluorescence microscopy; metronidazole; oseltamivir; drug assessment
• ISSN: 2076-0817; 2076-0817
• DOI: 10.3390/pathogens13050358

This study demonstrates the capability of Raman microscopy for detecting structural differences in
cells exposed to different drugs and incubation times. While metronidazole (MTZ) visibly affects the cells by inducing extracellular vesicle releases of toxic iron intermediates and modified triple-bond moieties, oseltamivir (OSM) alters the phenylalanine and lipid structures. Modifications in the heme protein environment and the transformation of iron from ferric to ferrous observed for both drug treatments are more notable for MTZ. Different contents and amounts of vesicle excretion are detected for 24 h or 48 h with MTZ incubation. At a shorter drug exposure, releases of altered proteins, glycogen, and phospholipids dominate. Agglomerates of transformed iron complexes from heme proteins and multiple-bond moieties prevail at 48 h of treatment. No such vesicle releases are present in the case of OSM usage. Drug incorporations into the cells and their impact on the plasma membrane and the dynamics of lipid raft confirmed by confocal fluorescence microscopy reveal a more destructive extent by OSM, corroborating the Raman results. Raman microscopy provides a broader understanding of the multifaceted factors and mechanisms responsible for giardiasis treatment or drug resistance by enabling a label-free, simultaneous monitoring of structural changes at the cellular and molecular levels.