Inhibition of Peroxidase Activity of Cytochromec: De Novo Compound Discovery and Validation

Abstract

Cytochrome c (cyt c) release from mitochondria is accepted to be the point of no return for eliciting a cascade of interactions that lead to apoptosis. A strategy for containing sustained apoptosis is to reduce the mitochondrial permeability pore opening. Pore opening is enhanced by peroxidase activity of cyt c gained upon its complexation with cardiolipin in the presence of reactive oxygen species. Blocking access to the heme group has been proposed as an effective intervention method for reducing, if not eliminating, the peroxidase activity of cyt c. In the present study, using a combination of druggability simulations, pharmacophore modeling, virtual screening, and in vitro fluorescence measurements to probe peroxidase activity, we identified three repurposable drugs and seven compounds that are validated to effectively inhibit the peroxidase activity of cyt c.

“Only a Life Lived for Others Is Worth Living”: Redox Signaling by Oxygenated Phospholipids in Cell Fate Decisions

“…The participation and essentiality of selective CL oxidation as a required mitochondrial stage of intrinsic apoptotic program has been demonstrated for many different types of wild-type cells. As expected, genetic manipulations causing deficiency of either CL-synthase as well as the entire cyt c or mutation of its Tyr 67 residue suppressed the apoptotic responses (5,9,62,95,97). Moreover, in several in vivo models with characteristic massive apoptotic death, such as hyperoxia in mice, inhalation exposure to single-walled carbon nanotube in mice, total body irradiation (TBI) in mice, and traumatic brain injury in ''pediatric'' rats-the accumulation of CL oxidation products has been confirmed by quantitative LC-MS-based oxidative lipidomics analysis (12,65,153,156,158).…”

Cytochrome c is an oxidative stress–activated plasmalogenase that cleaves plasmenylcholine and plasmenylethanolamine at the sn-1 vinyl ether linkage

“…2C). Interestingly, bifonazole, a cytochrome P450 inhibitor that inhibits the peroxidase activity of cyt c (45), potently inhibited cyt c-mediated plasmalogenase activity (Fig. 2C).…”

Known unknowns of cardiolipin signaling: The best is yet to come

“…As CL is a highly selective substrate of the peroxidase reaction (see below), CL peroxidation is a characteristic feature of apoptosis required for the completion of this death program [117]. Not surprisingly, substantial efforts have been directed towards design and development of new inhibitors of cyt c /CL peroxidase activity as anti-apoptotic modalities [118, 119]. In spite of numerous studies [120-125] the universal structural characterization of CL-driven activation of cyt c into a peroxidase still has not been achieved.…”