Ratiometric Near-Infrared Fluorescent Probe Monitors Ferroptosis in HCC Cells by Imaging HClO in Mitochondria

Abstract

Hypochlorous acid (HClO) is a typical endogenous ROS produced mainly in mitochondria, and it has strong oxidative properties. Abnormal HClO levels lead to mitochondrial dysfunction, strongly associated with various diseases. It has been shown that HClO shows traces of overexpression in cells of both ferroptosis and hepatocellular carcinoma (HCC). Therefore, visualization of HClO levels during ferroptosis of HCC is important to explore its physiological and pathological roles. So far, there has been no report on the visualization of HClO in ferroptosis of HCC. Thus, we present a ratiometric near-infrared (NIR) fluorescent probe Mito-Rh-S which visualized for the first time the fluctuation of HClO in mitochondria during ferroptosis of HCC. Mito-Rh-S has an ultrafast response rate (2 s) and large emission shift (115 nm). Mito-Rh-S was constructed based on the PET sensing mechanism and thus has a high signal-to-noise ratio. The cell experiments of Mito-Rh-S demonstrated that Fe 2+ -and erastin-induced ferroptosis in HepG2 cells resulted in elevated levels of mitochondrial HClO and that high concentration levels of Fe 2+ and erastin cause severe mitochondrial damage and oxidative stress and had the potential to kill HepG2 cells. By regulating the erastin concentration, erastin induction time, and treatment of the ferroptosis model, Mito-Rh-S can accurately detect the fluctuation of mitochondrial HClO levels during ferroptosis in HCC.

Activatable Fluorescent Probe for Studying Drug-Induced Senescence In Vitro and In Vivo

“…Consequently, aging stands as the primary risk factor linked to compromised tissue functionality and the onset of chronic ailments in humans. − Through extensive research on senescent cells, certain proteins and molecules, including senescence-associated β-galactosidase (SA-β-gal), p16INK4a, p53, p21, and IGFBP5, have emerged as commonly employed biomarkers associated with cellular senescence. − Throughout the process of cellular senescence, the concentration of reactive oxygen species (ROS) typically undergoes a progressive rise and can be influenced by a multitude of factors, resulting in varying degrees of fluctuation. − Consequently, preserving the equilibrium of ROS assumes significance in retarding cellular senescence. − HClO is a significant ROS with oxidative properties in biological systems. It originates from the breakdown of neutral HOCl and acts as a potent oxidizing agent that interacts with biomolecules within cells. , HClO plays a role in regulating intracellular signaling, inflammatory responses, and immune processes. − However, excessive levels of HClO can induce cellular oxidative stress, leading to damage in cellular structure and function, which accelerates cellular senescence and disease progression. − Therefore, comprehensive examinations of HClO during senescence are vital for enhancing our understanding of cellular senescence mechanisms, preventing age-related diseases, and devising antiaging strategies.…”

Ratiometric Fluorescent Probe for Super-Resolution Imaging of Lysosome HClO in Ferroptosis Cells

“…In recent years, fluorescent probes have become a promising tool for tracking and detecting HClO in live cells due to their advantages of noninvasiveness, high sensitivity, and ability to achieve in situ real-time detection at the cellular level in vivo. , HClO fluorescent probes for detecting ferroptosis developed so far are mainly based on the localization and identification of HClO in mitochondria. − MPO, an important lysosomal peroxidase, also causes an increase in the concentration of HClO in lysosomes during ferroptosis. , Therefore, real-time monitoring of HClO level changes in lysosomes during ferroptosis can also help researchers better understand the mechanism of ferroptosis. To the best of our knowledge, there is only one report that shows using a fluorescent probe to detect ferroptosis by sensing lysosome HClO .…”