A temperature-regulated bioorthogonal reaction to target lysine: Hemiacetal pharmacophore in genipin irreversibly binds with UCP2, inhibiting mitochondrial thermogenesis

Mitochondria are essential for eukaryotic life as powerhouses for energy metabolism. Excessive mitochondrial hyperthermia and reactive oxygen species (ROS) production have been associated with aging, cancer, neurodegenerative diseases, and other disorders. Uncoupling protein 2 (UCP2) is the effector responsible for regulating cellular thermogenesis and ROS production via dissipating protons in an electrochemical gradient. A UCP2 inhibitor named genipin (GNP) is being researched for its effect on mitochondrial temperature, but little is known about its mechanisms. This study developed several molecular probes to explore the interactions between GNP and UCP2. The result indicated that the hemiacetal structure in GNP could selectively react with the e -amine of lysine on the UCP2 proton leakage channel through ringopening condensation at the mitochondrial, cellular, and animal levels. A notable feature of the reaction is its temperature sensitivity and ability to conjugate with UCP2 at high fever as lysine-specific covalent inhibitors that prevent mitochondrial thermogenesis. The result not only clarifies the existence of an antipyretic properties of GNP via its irreversible coupling to UCP2, but also reveals a bioorthogonal reaction of hemiacetal iridoid aglycone for selectively binding with the e -amine of lysine on proteins. & COPY; 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

Mitochondria play a vital role in eukaryotic life by providing energy through metabolism. Excessive mitochondrial hyperthermia and reactive oxygen species (ROS) production are associated with various diseases. A UCP2 inhibitor called genipin (GNP) is being studied for its effects on mitochondrial temperature, but its mechanisms are not well understood. This study developed molecular probes to investigate the interactions between GNP and UCP2. The results showed that the hemiacetal structure in GNP selectively reacts with lysine in the UCP2 proton leakage channel, leading to inhibition of mitochondrial thermogenesis.