Evaluation of the involvement of prohibitin 1 (PHB) in the activation of STAT3 in macrophages

• Grant number: 18/17805-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2019
• End date: December 31, 2019
• Field of knowledge: Biological Sciences - Morphology - Cytology and Cell Biology
• Principal Investigator: Roger Chammas
• Grantee: Vitor Pedro Targhetta
• Host Institution: Instituto do Câncer do Estado de São Paulo Octavio Frias de Oliveira (ICESP). Coordenadoria de Serviços de Saúde (CSS). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Macrophages are a major component of the tumor microenvironment and its presence is generally associated with a worse tumor prognosis, enhancing tumor growth, drug resistance and local immunosupression. Pro-tumoral macrophages generally display an anti-inflammatory profile. Prohibitin 1 (PHB) is a protein with varied functions, with the most well known activities being related to cell cycle control, oxidative stress protection and as a mitochondrial chaperone. A considerable number of evidences discuss its participation in maintence of inflammation, highlighting its absence in inflammatory bowel diseases, its apparent regulation by TNF-a and IL-6, and its modulation in STAT3. The STAT3 pathway has been shown to be important in pro-tumoral and anti-inflammatory macrophages profiles. Data provided by our group suggests that IL-4 activated macrophages have a higher PHB protein level when compared to LPS and IFN-g activated macrophages. The function of PHB in macrophage activation is actually unknown. This project has as hypothesis that PHB is more expressed in anti-inflammatory macrophage activations and that silencing the PHB gene may interfere in macrophage activation by modulating STAT3. THP-1 cell line and bone marrow derived macrophages are going to be utilized for the experiments and, the following activation profiles will be performed: M(IL-4), M(IFN-g+LPS) and M(TAM-like). The location of PHB is going to be determined by immunofluorescence. PHB and STAT3 will be silenced by siRNA and anti and pro-inflammatory markers, as well as macrophage-monocyte differentiation markers, PHB and STAT3 will be verified by qRT-PCR. Phosphorilated STAT3 is going to be verified by Western Blot.