Directing Function at the NK cell Immune Synapse
NK cells represent an essential fraction of the innate immune system, readily capable to eliminate virally infected or transformed and cancerous cells. Among several mechanisms, the most important one involved in this lethal activity requires the delivery of the toxic content from highly specialized lysosome-related organelles in NK cells called lytic granules from the NK cell onto the target after the formation of a unique cell-cell interface named the immune synapse. This unique structure, and the understanding of the complex cellular processes that govern its formation and function, has been at the center of our research programs, and we have defined many discrete steps that contribute to contact-dependent cytotoxicity (NIH-NIAID R01AI-067946-06). The progression through these checkpoints is tightly regulated to maintain homeostasis, precision in killing diseased cells, and their understanding allows us to appreciate the diversity of molecular mechanisms in place. These approaches have also allowed us to elucidate many defects observed in immunodeficiency diseases and more specific NK cell deficiencies in human patients.
Ultimately, exposing the biological machinery behind this directed secretion of lytic granules will allow us to modulate, and even enhance, this essential host defense process. To achieve these aims, we combine cutting-edge cell biological techniques, particularly high- and super-resolution imaging, with manipulation of human NK cell lines to investigate the human NK cell immune synapse with unprecedented resolution. We have a particular focus on understanding how the cytoskeleton orchestrates the targeted delivery of lytic granules to effectively mediate target cell lysis. The ability to better understand the mechanics and biophysics of this process has led to strategies by which we may better harness the lethal functions of NK cells. Given the rapid growth of the field of cellular therapeutics we are optimistic that advanced tools derivative from these cell biological and immunobiological studies will give us new strategies to improve existing cellular therapies and treatments for cancer and viral disease.
Genetic, Immunologic and Mechanistic Basis of Human NK cell Deficiency
The Orange Lab is intensely focused on understanding what enables most individuals to remain healthy despite continuous challenges from our environment. In particular, we are interested in patients with primary immunodeficiencies in which inborn errors of immunity lead to breakdown of the human immune system and subsequent disease. We are especially interested in human natural killer cells and the roles that they play in maintaining immunity and preventing malignancy. To better understand the requirement for NK cells in human health, we identify patients with natural killer cell deficiencies (NKD) through cutting-edge genetic and genomic technologies (NIH-NIAID R01AI120989). This approach is complemented by state-of-the-art cell biological techniques to dissect the mechanism by which gene mutations can affect NK cell development, function or both. We have significant expertise in modeling patient mutations in NK cell lines, gene editing and microscopy and image analysis, including super-resolution microscopy. Using these approaches, we have identified novel NKD including biallelic IRF8 deficiency, GATA2 deficiency, and FCGR3A mutation as a cause of functional NKD. In addition, we actively investigate primary immunodeficiencies that may or may not include an element of NK cell dysfunction, including Wiskott-Aldrich Syndrome, COPA syndrome, hemophagocytic lymphohistiocytosis, POMP-related autoinflammation and immune dysregulation disease (PRAID) and more.