Role of endogenous hydrogen sulfide (H2S) in the inflammatory response induced by bacterial membrane lipopolysaccharide (LPS) on cultured THP-1 macrophages

• Grant number: 25/12825-1
• Support Opportunities: Regular Research Grants
• Start date: October 01, 2025
• End date: September 30, 2026
• Field of knowledge: Biological Sciences - Pharmacology - Biochemical and Molecular Pharmacology
• Principal Investigator: Marcelo Nicolas Muscara
• Grantee: Marcelo Nicolas Muscara
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• City of the host institution: São Paulo
• Associated research grant: 23/13436-3 - Study on the effects of the mitochondria-targeted hydrogen sulfide (H2S)-donor AP39 on vascular endothelial and smooth muscle cells in culture., AP.R
• Associated scholarship(s): 25/22739-5 - Role of endogenous hydrogen sulfide (H2S) in the inflammatory response induced by bacterial membrane lipopolysaccharide (LPS) on cultured THP-1 macrophages., BP.IC

Abstract

Hydrogen sulfide (H2S) is a gaseous mediator produced endogenously by several cells, including macrophages, through the enzymes CSE, CBS and 3-MST. Evidence indicates that H2S can exert modulatory effects on the inflammatory response, but the mechanisms involved are not yet fully understood. This project aims to investigate the role of endogenous H2S in the inflammatory response in differentiated THP-1 macrophages, both under basal conditions and after stimulation with lipopolysaccharide (LPS).After differentiation of THP-1 monocytes into macrophages, the cells will be treated with LPS for 24 hours, with or without pretreatment with H2S biosynthesis inhibitors (DL- propargylglycine - PAG or amino-oxo-butanoic acid - BCA). H2S production will be quantified in cell homogenates by the lead sulfide (PbS) formation method. Protein expression of H2S- producing enzymes (CBS, CSE, 3-MST) and iNOS will be analyzed by Western blot. The inflammatory response will be assessed by measuring pro-inflammatory cytokines (IL-1beta, TNF-alpha, IL-6) by ELISA, and nitric oxide (NO) production, quantified indirectly by the Griess method. To ensure that the observed effects are not due to cellular toxicity, cell viability (MTT) and membrane integrity (LDH activity) assays will be performed.The expected results may contribute to the understanding of the role of H2S in controlling inflammation, providing support for the development of new therapeutic strategies in inflammatory diseases. (AU)