The liver kinase B1 is a central regulator of T cell development, activation, and metabolism.

Abstract

T cell activation leads to engagement of cellular metabolic pathways necessary to support cell proliferation and function. However, our understanding of the signal transduction pathways that regulate metabolism and their impact on T cell function remains limited. The liver kinase B1 (LKB1) is a serine/threonine kinase that links cellular metabolism with cell growth and proliferation. In this study, we demonstrate that LKB1 is a critical regulator of T cell development, viability, activation, and metabolism. T cell-specific ablation of the gene that encodes LKB1 resulted in blocked thymocyte development and a reduction in peripheral T cells. LKB1-deficient T cells exhibited defects in cell proliferation and viability and altered glycolytic and lipid metabolism. Interestingly, loss of LKB1 promoted increased T cell activation and inflammatory cytokine production by both CD4(+) and CD8(+) T cells. Activation of the AMP-activated protein kinase (AMPK) was decreased in LKB1-deficient T cells. AMPK was found to mediate a subset of LKB1 functions in T lymphocytes, as mice lacking the α1 subunit of AMPK displayed similar defects in T cell activation, metabolism, and inflammatory cytokine production, but normal T cell development and peripheral T cell homeostasis. LKB1- and AMPKα1-deficient T cells each displayed elevated mammalian target of rapamycin complex 1 signaling and IFN-γ production that could be reversed by rapamycin treatment. Our data highlight a central role for LKB1 in T cell activation, viability, and metabolism and suggest that LKB1-AMPK signaling negatively regulates T cell effector function through regulation of mammalian target of rapamycin activity.

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Citation

Published Version (Please cite this version)

10.4049/jimmunol.1100367

Publication Info

MacIver, Nancie J, Julianna Blagih, Donte C Saucillo, Luciana Tonelli, Takla Griss, Jeffrey C Rathmell and Russell G Jones (2011). The liver kinase B1 is a central regulator of T cell development, activation, and metabolism. J Immunol, 187(8). pp. 4187–4198. 10.4049/jimmunol.1100367 Retrieved from https://hdl.handle.net/10161/10316.

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Scholars@Duke

MacIver

Nancie Jo MacIver

Adjunct Associate Professor in the Department of Pediatrics

My laboratory is broadly interested in how large changes in nutritional status (e.g. malnutrition or obesity) influence T cell immunity.  Malnutrition can lead to immunodeficiency and increased risk of infection, whereas obesity is associated with inflammation that promotes multiple diseases including autoimmunity, type 2 diabetes, and cardiovascular disease.  We have identified the adipocyte-secreted hormone leptin as a critical link between nutrition and immunity.  Leptin is secreted from adipocytes in proportion to adipocyte mass and is therefore decreased in malnutrition and increased in obesity.  We have found that leptin is a critical regulator of effector T cell glucose metabolism and thereby drives effector T cell activation.  From these initial findings, we have established further lines of investigation, as summarized here.

(1) Determining molecular mechanisms of T cell dysfunction in malnutrition – Our goal is to identify metabolic and epigenetic mechanisms by which malnutrition and decreased leptin alter T cell function leading to increased susceptibility to infection and protection against autoimmune diseases.  We study this using a mouse model of autoimmunity, experimental autoimmune encephalomyelitis (EAE).

(2) Elucidating mechanisms of T cell inflammation in obesity-induced type 2 diabetes – Our goal is to identify molecular and metabolic mechanisms by which obesity alters the Teff/Treg balance, resulting in inflammation and subsequent insulin resistance leading to type 2 diabetes.  With our collaborators from UNC Chapel Hill, we are also identifying immunometabolic changes in obese animals and humans that correlate with increased susceptibility to influenza.

(3) Determining the role of insulin and IGF-1 in regulating T cell function and metabolism – Our goal is to identify how insulin influences both T cell glucose uptake and T cell differentiation/cytokine production and determine the role of insulin signaling in T cells in the setting of obesity-associated diabetes.  We hypothesize that insulin has a direct role in T cell function through its abiltiy to alter T cell glucose metabolism, influence T cell cytokine production, and impact the pathophysiology of obesity-associated type 2 diabetes. 


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