ITAGradation: Elucidating C5 itaconate degradation pathway and 2-hydroxymethyl succinate in inflammation

• Applicant: Professorin Dr. Thekla Cordes
• Subject Area: Cell Biology ; Endocrinology, Diabetology, Metabolism
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 555979574

Metabolic reprogramming is emerging as a hallmark of the innate immune response, and the dynamic control of metabolites such as succinate serves to facilitate the execution of inflammatory responses in macrophages and other immune cells. Immunoresponsive gene 1 (Irg1) expression is induced by inflammatory stimuli, and its enzyme product cis-aconitate decarboxylase catalyzes the production of itaconate from the tricarboxylic acid cycle. Itaconate is endogenously present in humans and accumulates at mM levels to modulate immune cell metabolism and function. Specifically, itaconate inhibits succinate dehydrogenase (SDH) activity modulating mitochondrial metabolism, including the TCA cycle and BCAA metabolism as well as CoA homeostasis. However, how itaconate is metabolized further is not well understood. In preliminary studies, we identified that the novel metabolite 2-hydroxymethyl succinate (2HMS) is derived from itaconate and that this metabolite has not been described as present in mammalian cells. In this proposal, we will explore the C5 dicarboxylate pathway of itaconate dissimilation focusing on the metabolic and functional roles of 2HMS and citramalate in inflammation. We will also decipher the synthesis pathway of this novel mammalian metabolite 2HMS. The potential roles of C5 dicarboxylate metabolism and itaconate-derived compounds will be explored in three Specific Objectives: Objective 1. Identify the metabolic and functional consequences of 2HMS on immune cell metabolism. We will modulate intracellular itaconate levels to access the synthesis of 2HMS and apply metabolic flux analysis to immune cells to evaluate the metabolic and signaling mechanisms through which 2HMS impacts cell function. Objective 2. Characterize the impact of altered citramalate metabolism. Citramalate synthesis will be analyzed by altering itaconate metabolism. We will also dissect the role of citramalate in influencing cellular functions focusing on immune responses. Objective 3: Dissect the C5 dicarboxylate metabolic pathway of itaconate dissimilation. We will study the itaconate dissimilation pathway in genetically engineered cell lines targeting potential enzymes involved in 2HMS and citramalate synthesis pathway. We will also explore potential other intermediates of the itaconate dissimilation pathway. This project will merge expertise in mass spectrometry, immunometabolism, in-depth metabolic pathway studies, and itaconate metabolism. We aim to decipher the functional roles of 2HMS and citramalate and to identify potential metabolic vulnerabilities influencing inflammatory outcomes. Ultimately, our results are expected to advance the development of new and improved therapeutic strategies for inflammatory diseases associated with itaconate metabolism.

• DFG Programme: Research Grants