MAGIC · Deciphering the biology of Multinucleated Alveolar Giant cells In Chronic inflammation

Multinucleated Giant Cells (MNGCs) arise from the fusion of myeloid cells and are subclassified into osteoclasts, foreign body giant cells, and Langhans giant cells. While osteoclasts are well-characterized in bone physiology, the biology of inflammation-induced MNGCs remains poorly understood. Recent findings from the Lambrecht lab identified an IRF4-dependent transcriptional program in alveolar macrophages (AMs) that drives their fusion into MNGCs in a murine model of IL-33-induced eosinophilic airway inflammation. To dissect these processes, the lab developed the SPAM-deleter model, allowing timed depletion and reconstitution of AMs for precise in vivo analysis of MNGC formation. Additionally, lipid nanoparticle–mediated guide RNA delivery enables rapid CRISPR-Cas9 gene editing in primary AMs in vivo and ex vivo, thus eliminating the need for new mouse lines. These innovative tools create an unprecedented opportunity to uncover the cellular and molecular mechanisms driving inflammatory MNGC formation and function.I hypothesize that during inflammation, AMs fuse into MNGCs in an osteoclast-like manner, modulate lung tissue function, and later dissociate into individual AMs to repopulate the niche upon resolution of inflammation.To test this, I will:- Identify the molecular and cellular drivers of lung MNGC fusion- Determine the fate of MNGCs after resolution of inflammation- Define the functional role of MNGCs in chronic lung inflammationThis project will generate novel resources for MNGC research including their transcriptional profile and a MNGC deficient mouse model. While centered on MNGC formation and fate, this project ultimately aims to determine how MNGCs contribute to chronic lung inflammation and how their formation can be therapeutically modulated. By identifying key mechanisms and players, this work will lay the foundation for future strategies to target MNGCs in inflammatory lung disease.