Prerequisites for ubiquinone analogs to prevent mitochondrial permeability transition-induced cell death

Area of Science:

• Mitochondrial physiology
• Cell death mechanisms
• Oxidative stress

Background:

• The mitochondrial permeability transition pore (PTP) is a key regulator of cell death.
• Inhibiting PTP opening is a promising strategy against oxidative stress-induced cell death.
• Ubiquinone analogs show varied effects on PTP opening across different cell types.

Purpose of the Study:

• To investigate the effects of ubiquinone 0 (Ub(0)), ubiquinone 5 (Ub(5)), and ubiquinone 10 (Ub(10)) on PTP regulation.
• To assess the impact of these ubiquinones on hydrogen peroxide (H(2)O(2)) production and cell viability in U937 cells.
• To determine the relationship between ubiquinone pro-oxidant activity and their ability to prevent PTP-induced cell death.

Main Methods:

• Treatment of U937 cells with Ub(0), Ub(5), and Ub(10).
• Measurement of PTP opening, H(2)O(2) production, and cell viability.
• Evaluation of ubiquinone effects on tert-butyl hydroperoxide-induced cell death.

Main Results:

• Ub(0) induced PTP opening and H(2)O(2) production, leading to cell death.
• Ub(5) induced H(2)O(2) production but did not regulate PTP opening, causing cell death.
• Ub(10) potently inhibited PTP opening, induced minimal H(2)O(2) production, was non-toxic, and protected against oxidative stress-induced cell death.

Conclusions:

• Ubiquinone analogs' efficacy in preventing PTP-induced cell death is contingent on their inherent toxicity and pro-oxidant activity.
• Non-toxic ubiquinone analogs with low pro-oxidant activity, such as Ub(10), are effective PTP inhibitors and cytoprotective agents.
• The findings highlight the critical role of balancing PTP inhibition with minimal pro-oxidant effects for therapeutic potential.