Biology subjects

Connolly, J. E.

Publications and source records attributed to Connolly, J. E..

3 recordsLinked to original sources

bioRxiv2020

LAG3 is a Central Regulator of NK Cell Cytokine Production

Natural killer (NK) cells are innate effectors, which play a crucial role in controlling viral infections. Administration of IFN- has shown promising results as a therapeutic, controlling HIV, and chronic viral hepatitis. However the downstream mechanisms by which IFN- mediates its anti-viral effects is largely unknown. In this investigation, we evaluated the impact of IFN- on peripheral blood NK cells from healthy donors. High dimensional flow cytometry analysis of NK cell surface receptors following exposure to IFN- showed an increased expression of the check point inhibitor LAG3. Further characterization revealed that LAG3 was expressed in a subset of NK cells with high expression of activation and maturation markers. Assessment of metabolic pathways showed that LAG3+ NK cells had enhanced rates of glycolysis and glycolytic capacity, suggesting that it is a primed effector subset with enhanced glucose metabolism. Inhibition of LAG3 on NK cells using antibody in vitro resulted in a profound increase in secretion of cytokines IFN-{gamma}, TNF-, MIP-1 and MIP-1{beta}, without affecting the cytotoxic activity. Taken together, these results showed that LAG3 is a negative regulator of cytokine production by mature NK cells.

immunology↗

bioRxiv2020

A novel strategy for single-cell metabolic analysis highlights dynamic changes in immune subpopulations

A complex interaction of anabolic and catabolic metabolism underpins the ability of leukocytes to mount an immune response. Their capacity to respond and adapt to changing environments by metabolic reprogramming is crucial to their effector function. However, current methods lack the ability to interrogate this network of metabolic pathways at the single cell level within a heterogeneous population. Here we present Met-Flow, a novel flow cytometry-based method that captures the metabolic state of immune cells by targeting key proteins and rate-limiting enzymes across multiple pathways. We demonstrate the ability to simultaneously measure divergent metabolic profiles and dynamic remodeling in human peripheral blood mononuclear cells. Using Met-Flow, we discovered that glucose restriction and metabolic remodeling drive the expansion of an inflammatory central memory T cell subset. This method captures the complex metabolic state of any cell as it relates to its phenotype and function, leading to a greater understanding of the role of metabolic heterogeneity in immune responses.

immunology↗

bioRxiv2018

DPP9 is an endogenous and direct inhibitor of the NLRP1 inflammasome that guards against human auto-inflammatory diseases

The inflammasome is a critical immune complex that activates IL-1 driven inflammation in response to pathogen- and danger-associated signals. Nod-like receptor protein-1 (NLRP1) is a widely expressed inflammasome sensor. Inherited gain-of-function mutations in NLRP1 cause a spectrum of human Mendelian diseases, including systemic autoimmunity and skin cancer susceptibility. However, its endogenous regulation and its cognate ligands are still unknown. Here we apply a proteomics screen to identify dipeptidyl dipeptidase, DPP9 as a novel interacting partner and a specific endogenous inhibitor of NLRP1 inflammasome in diverse primary cell types from human and mice. DPP9 inhibition via small molecule drugs, targeted mutations in its catalytic site and CRISPR/Cas9-mediated genetic deletion potently and specifically activate the NLRP1 inflammasome leading to pyroptosis and IL-1 processing via ASC and caspase-1. Mechanistically, DPP9 maintains NLRP1 in its monomeric, inactive state by binding to the auto-cleaving FIIND domain. NLRP1-FIIND is a self-sufficient DPP9 binding module and its disruption by a single missense mutation abrogates DPP9 binding and explains the aberrant inflammasome activation in NAIAD patients with arthritis and dyskeratosis. These findings uncover a unique peptidase enzyme-based mechanism of inflammasome regulation, and suggest that the DPP9-NLRP1 complex could be broadly involved in human inflammatory disorders.

immunology↗