Study of HIF-1alpha stabilization dynamics by ROS and its relation with NF-kB pathway in the induction of macrophages pro-inflammatory profile

• Grant number: 21/10544-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2021
• End date: November 30, 2022
• Field of knowledge: Biological Sciences - Immunology - Cellular Immunology
• Principal Investigator: Pedro Manoel Mendes de Moraes Vieira
• Grantee: Guilherme Ribeiro da Silva
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Macrophages are essential cells for tissue homeostasis and constitute the first line of host defense. Macrophages activated with LPS and IFN-³ acquire a pro-inflammatory profile characterized by NF-kB activation, which in turn induces cytokine expression, such as IL-6, IL-1², and TNF-±, and the production of nitric oxide by inducible nitric oxide synthase (iNOS). To acquire this profile, macrophages shift to glycolytic metabolism, at the same time that ATP generation mediated by the electron transport chain is reduced. Beyond that, the tricarboxylic acids cycle (TCA) has intermediates that deviated to another pathway and it uses the glutamine metabolism to ±-ketoglutarate production in TCA. The succinate oxidation by succinate dehydrogenase (SDH), together with augmented membrane potential, contributes to oxygen reactive species (ROS) production. It has also been demonstrated that mitochondrial glycerol-3-phosphate dehydrogenase (GPD2) is related to cytokine and ROS production. Mitochondria-derived ROS can stabilize the hypoxia-inducible factor-1± (HIF-1±), which induces genes related to the glycolytic pathway (Ldh, Pkm2, and Pfkfb3) and genes related to inflammation (Il-1²). HIF-1± depletion in macrophages reduces the pro-inflammatory and glycolytic profile of these cells and glycolysis blockade reduces HIF-1± levels but affects in different ways IL-6, IL-1², and TNF-± expression. The use of 2DG, a hexokinase competitive inhibitor, affects IL-6, IL-1², and TNF-± expression differently than when glucose is absent of the medium. Besides that, it is not known the contribution of different ROS sources for HIF-1± stabilization and if HIF-1± controls directly NF-kB activation. Then, this work aims to analyze how different carbon sources affect ROS production, HIF-1± activation, and pro-inflammatory profile induction, mediated by NF-kB. (AU)