Identification and selection of inhibitors and/or activators of enzymes involved in the formation and detoxification of oxidized lipids

• Grant number: 21/10514-8
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): October 01, 2021
• Effective date (End): August 31, 2024
• Field of knowledge: Biological Sciences - Biochemistry
• Principal Investigator: Sayuri Miyamoto
• Grantee: Lucas Gasparello Viviani
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 13/07937-8 - Redoxome - Redox Processes in Biomedicine, AP.CEPID

Abstract

In mammals, formation and detoxification of oxidized lipids are catalysed, among other enzymatic systems, by lipoxygenases and peroxidases, respectively. Some human lipoxygenases, including 5-lipoxygenase (5-LOX) and 15-lipoxygenases (15-LOX-1 and 15-LOX-2), participate in the biosynthesis of pro-inflammatory and pro-resolution lipid mediators and play important roles as modulators of inflammatory responses in different pathophysiological contexts. Two important peroxidases, glutathione peroxidase 4 (GPx4) and peroxiredoxin 6 (Prx6), can reduce phospholipid hydroperoxides in cellular membranes. Human GPx4 and, recently, human Prx6 have attracted great attention due to their roles in ferroptosis, a non-apoptotic and druggable cell death pathway characterized by iron-dependent lipid peroxidation, which has been implicated in processes such as neurodegeneration, tumorigenesis, and ischemia-reperfusion injury. Due to the importance of their biological and pathophysiological roles, the enzymes mentioned above (human lipoxygenases 5-LOX, 15-LOX-1, and 15-LOX-2 and human peroxidases GPx4 and Prx6) have been recognized as promising biological targets for the pharmacological treatment of many human diseases, including cancer and neurodegenerative, cardiovascular, and pulmonary diseases. Nevertheless, only a few inhibitors and/or activators of those enzymes have been described in the literature and, with a few exceptions (e.g., zileuton, a 5-LOX inhibitor), none of them has been approved for clinical use so far. In addition, most of the known inhibitors have structural, physicochemical, and pharmacological characteristics that limit their applicability as drug candidates, such as poor solubility, low inhibitory potency, lack of selectivity, and high cytotoxicity. Therefore, searching for novel modulators of the mentioned lipoxygenases and peroxidases is an urgent need. To address this issue, this project aims to: (A) select novel inhibitors and/or activators of the following target enzymes: (I) human 5-LOX, 15-LOX-1, and 15-LOX-2 and (II) human GPx6 and Prx6, by Virtual Screening (VS) applied to commercially available compound databases, using Structure-Based Drug Design (SBDD) and Ligand-Based Drug Design (LBDD) approaches; (B) experimentally validate the generated VS models through in vitro enzymatic assays; and (C) evaluate the effects of the inhibition/activation of the target enzymes in the lipid metabolism and in the oxidized lipid profile in specific cell models, using advanced lipidomic and oxylipidomic techniques. Overall, we expect to identify novel classes of inhibitors and/or activators of lipoxigenases and peroxidases, which would represent starting structures for the design of potential drug candidates for treating human diseases. (AU)