Related Experiment Video
Updated: Mar 24, 2026
Simultaneous Measurement of Mitochondrial Calcium and Mitochondrial Membrane Potential in Live Cells by Fluorescent Microscopy
Published on: January 24, 2017
Identification of a Small Molecule Cyclophilin D Inhibitor for Rescuing Aβ-Mediated Mitochondrial Dysfunction
Koteswara Rao Valasani1, Qinru Sun2, Du Fang1
1Department of Pharmacology & Toxicology and Higuchi Bioscience Center, School of Pharmacy, University of Kansas , Lawrence, Kansas 66047, United States.
Abstract:
Cyclophilin D (CypD), a peptidylprolyl isomerase F (PPIase), plays a central role in opening the mitochondrial membrane permeability transition pore leading to cell death. CypD resides in the mitochondrial matrix, associates with the inner mitochondrial membrane, interacts with amyloid beta to exacerbate mitochondrial and neuronal stress and has been linked to Alzheimer's disease (AD). We report the biological activity of a small-molecule CypD inhibitor (C-9), which binds strongly to CypD and attenuates mitochondrial and cellular perturbation insulted by Aβ and calcium stress. Binding affinities for C-9 were determined using in vitro surface plasmon resonance. This compound antagonized calcium-mediated mitochondrial swelling, abolished Aβ-induced mitochondrial dysfunction as shown by increased cytochrome c oxidase activity and adenosine-5'-triphosphate levels, and inhibited CypD PPIase enzymatic activity by real-time fluorescence capture assay using Hamamatsu FDSS 7000. Compound C-9 seems a good candidate for further investigation as an AD drug.
Insights
A novel inhibitor, C-9, targets cyclophilin D (CypD) to protect mitochondria from stress. This Alzheimer's disease drug candidate reduces neuronal damage caused by amyloid beta and calcium.
Area of Science:
- Mitochondrial biology
- Neuroscience
- Pharmacology
Background:
- Cyclophilin D (CypD) is a mitochondrial enzyme implicated in cell death pathways.
- CypD contributes to mitochondrial and neuronal stress, particularly in Alzheimer's disease (AD), through interactions with amyloid beta (Aβ).
Purpose of the Study:
- To evaluate the biological activity of a novel small-molecule inhibitor, C-9, targeting CypD.
- To assess C-9's efficacy in mitigating Aβ and calcium-induced mitochondrial and cellular dysfunction relevant to AD.
Main Methods:
- Surface plasmon resonance was used to determine C-9 binding affinities to CypD.
- In vitro assays measured C-9's effects on calcium-mediated mitochondrial swelling, Aβ-induced mitochondrial dysfunction (cytochrome c oxidase activity, ATP levels), and CypD's peptidylprolyl isomerase (PPIase) enzymatic activity.
Main Results:
- Compound C-9 demonstrated strong binding to CypD.
- C-9 effectively antagonized calcium-induced mitochondrial swelling.
- The inhibitor abolished Aβ-induced mitochondrial dysfunction and inhibited CypD's PPIase activity.
Conclusions:
- Small-molecule CypD inhibitor C-9 attenuates mitochondrial and cellular perturbations.
- C-9 shows promise as a therapeutic candidate for Alzheimer's disease treatment.
