New Lipid Metabolic Targets for Treatment of Inflammation

Abstract

Abstract The human genome contains a vast number of enzymes that lack functional annotation. As a result, our basic understanding of enzymatic pathways that underlie human physiology and pathology remains largely incomplete. Molecular profiling technologies have emerged as an unbiased means to globally examine the biochemical makeup of cells and tissues and identify genes and proteins associated with pathophysiological states. In contrast, global methods for the functional characterization of enzymatic pathways in native biological systems are still lacking. I will describe our efforts to integrate activity-based protein profiling (ABPP) with functional proteomic/metabolomics methods to map novel bioactive lipid networks involved in inflammation. I will describe the development of the first selective and in vivo-active small-molecule inhibitors for the 2-arachidonoylglycerol (2-AG) biosynthetic enzyme, diacylglycerol lipase-beta (DAGLB), along with paired negative-control and tailored activity-based probes for the functional analysis of DAGLB in living systems. We utilize our newly developed chemical probes to discover and show that DAGLB inactivation lowers 2-AG production in mouse peritoneal macrophages, as well as arachidonic acid and eicosanoids in a manner that is distinct and complementary to cytosolic phospholipase-A2. A corresponding reduction in lipopolysaccharide (LPS)-induced TNF-alpha release was observed, indicating that DAGLB serves as a key metabolic hub within a lipid signaling network that regulates proinflammatory responses in macrophages. We will present recent findings that identify DAGLB as a promising anti-inflammatory target for treatment of inflammatory and neuropathic pain.