Project Summary/Abstract
Monocytes and macrophages function in diverse processes, from homeostatic
maintenance to immune responses and tissue regeneration. These functions are
coordinated with and strongly influenced by cellular metabolism via mechanisms that are
increasingly studied and characterized in populations of macrophages. However, such
studies mask the cell-to-cell variation which is an inherent property of macrophage
diversity. Indeed, single-cell transcriptomics data have demonstrated that macrophage
polarization is better described by continuous gradients rather than by discrete states
amenable to isolation and population analysis. Yet, transcriptional measurements are
insufficient to characterize the metabolic and protein networks that shape monocyte and
macrophage diversity. To understand how these networks control macrophage
polarization and functions, we propose to directly quantify proteins and regulatory signals
(such as localization of key regulators, e.g., NF-¿B) in primary human monocytes and
macrophages responding to physiologically relevant metabolic environments.
Furthermore, we will extend this single-cell analysis to the responses of these cells to
pathogen-associated molecular patterns and damage-associated molecular patterns.
These data will enable us to identify likely regulatory networks driving monocyte and
macrophage responses to metabolic states and molecular patterns. Subsequently, we
will test these networks via pharmacological and genetic perturbations. We are uniquely
positioned to perform this research since we recently pioneered methods for quantifying
thousands of proteins across many single cells. Furthermore, we have the required
expertise in analyzing metabolic systems (including aerobic glycolysis, which is frequently
associated with macrophage activation) and developing new algorithms for data
analysis. This project will advance our understanding of macrophage immunometabolism
and polarization, will introduce methods for more sensitive and accurate single-cell
analysis, and will provide a proof-of-principle demonstration of the possibility to identify
protein-mediated molecular mechanisms at single-cell resolution. We strongly believe
that attaining these goals will have a transformative impact on biomedical research
and will inform new and better therapeutic strategies.