A two-photon fluorescent probe for imaging of mitochondrial cysteine in λ-carrageenan induced arthritis

Arthritis is an inflammatory and autoimmune disease seriously affecting the quality of a patient’s life, and its pathogenesis remains obscure. Mitochondrial oxidative stress is involved in the patho-physiology of arthritis. Cystein (Cys) plays a crucial role as a free radical scavenger in oxidative stress, and thus decreased mitochondrial Cys might be observed in mice with arthritis. To verify this inference, we report a two-photon imaging probe for fluorescence measurement of mitochondrial Cys with high selectivity and good sensitivity. InCYS can track Cys in situ through one-photon and two-photon fluorescence imaging in vivo . By using InCYS, we successfully revealed decreases in the levels of mitochondrial Cys in the ankles of mice with arthritis. This work provides an effective bio-target for the development of novel therapeutic approaches for arthritis, and a practical tool for revealing the connections between mitochondrial oxidative stress and severe diseases.