Versatile Fluorescence Lifetime-Based Copper Probe to Quantify Mitochondrial Membrane Potential and Reveal Its...

Area of Science:

• Biochemistry
• Cell Biology
• Neuroscience

Background:

• Mitochondria are vital for cellular homeostasis; mitochondrial membrane potential (MMP) depolarization signals apoptosis.
• Protein misfolding and aggregation are implicated in diseases like neurodegenerative disorders, diabetes, and cancer.
• The interplay between MMP changes and disease-related protein aggregation remains understudied.

Purpose of the Study:

• To develop and utilize a novel fluorescent probe for in situ copper ion (Cu2+) detection in mitochondria.
• To quantitatively assess mitochondrial membrane potential (MMP) changes during SOD1 (A4V) protein aggregation.
• To elucidate the relationship between copper, MMP depolarization, and protein aggregation.

Main Methods:

• Development of a novel "turn-on" fluorescent probe, MitoRhB, targeting mitochondria for Cu2+ detection.
• Utilizing fluorescence lifetime (τ) measurements of MitoRhB to correlate with MMP.
• Quantitative analysis of MMP during SOD1 (A4V) protein aggregation.

Main Results:

• MitoRhB fluorescence lifetime (τ) positively correlates with MMP, enabling quantitative MMP assessment.
• Increasing copper concentrations accelerate mitochondrial depolarization, reducing MMP.
• Mitochondrial depolarization intensifies protein aggregation.

Conclusions:

• Copper ions accelerate mitochondrial depolarization, impacting MMP.
• Mitochondrial depolarization exacerbates protein aggregation.
• A novel pathway for copper-induced cell death involving MMP depolarization and protein aggregation is proposed.