The long-term objective of this proposal is to gain insight into vitamin D-dependent mechanisms of innate and adaptive immunity in humans. Our previous work has revealed a new immunologic paradigm which underscores the importance of adequate circulating 25-hydroxyvitamin D (25D) levels for human host defense against microbial infection. We demonstrated that in human macrophages: innate and adaptive mechanisms activate different receptors but converge on a common vitamin D receptor (VDR)-driven antimicrobial pathway against M. tuberculosis (mTB) involving the induction of IL-15 and the the vitamin D-1?-hydroxylase (CYP27b1), which converts 25D to the active metabolite 1,25-dihydroxyvitamin D (1,25D). Subsequent activation of the VDR induces downstream genes coding for the antimicrobial peptides cathelicidin and DEFB4, together with induction of autophagy, result in antimicrobial activity. Strikingly, this antimicrobial pathway was dependent on levels of 25D, which also correlate with susceptibility to tuberculosis in humans. Our central hypothesis is that adequate circulating 25D levels are critically required for effective innate and adaptive immune responses against mTB, which we will test according to the following specific aims: 1) define the distinct and interactive roles of IL-15 and IL-32 in the induction of the 25D-dependent antimicrobial pathway, 2) investigate counter-regulation of antimicrobial activity by Type I IFNs; and 3) determine the effects of 25D availability on dendritic cell (DC) function. The proposed studies will provide new information about the mechanisms of human innate and adaptive immunity with specific relevance to TB but of significance to the potential use of simple, inexpensive vitamin D supplementation as an adjunct to prevention and therapy of infectious disease.

Public Health Relevance

We have chosen to study the mechanisms by which vitamin D contributes to human immune responses against tuberculosis (TB) because: 1) the disease poses a major infectious disease risk especially with the emergence of multidrug resistant strains, and, 2) the disease provides a model to understand the mechanisms by which low levels of 25-hydroxyvitamin D, the form measured in the clinical blood test, result in susceptibility to infection. The insights gained from the study of the vitamin D antimicrobial pathway provide the potential for therapeutic intervention with vitamin D, costing a few dollars, in augmenting human immune responses as part of prevention of infectious disease and as an adjuvant to therapy.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
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Immunity and Host Defense (IHD)
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Caler, Elisabet V
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University of California Los Angeles
Internal Medicine/Medicine
Schools of Medicine
Los Angeles
United States
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Kim, Elliot W; Teles, Rosane M B; Haile, Salem et al. (2018) Vitamin D status contributes to the antimicrobial activity of macrophages against Mycobacterium leprae. PLoS Negl Trop Dis 12:e0006608
Steiger, Julia; Stephan, Alexander; Inkeles, Megan S et al. (2016) Imatinib Triggers Phagolysosome Acidification and Antimicrobial Activity against Mycobacterium bovis Bacille Calmette-Guérin in Glucocorticoid-Treated Human Macrophages. J Immunol 197:222-32
Realegeno, Susan; Kelly-Scumpia, Kindra M; Dang, Angeline Tilly et al. (2016) S100A12 Is Part of the Antimicrobial Network against Mycobacterium leprae in Human Macrophages. PLoS Pathog 12:e1005705
Kibbie, Jon; Teles, Rosane M B; Wang, Zhiming et al. (2016) Jagged1 Instructs Macrophage Differentiation in Leprosy. PLoS Pathog 12:e1005808
Schenk, Mirjam; Mahapatra, Sebabrata; Le, Phuonganh et al. (2016) Human NOD2 Recognizes Structurally Unique Muramyl Dipeptides from Mycobacterium leprae. Infect Immun 84:2429-38
Inkeles, Megan S; Teles, Rosane M B; Pouldar, Delila et al. (2016) Cell-type deconvolution with immune pathways identifies gene networks of host defense and immunopathology in leprosy. JCI Insight 1:e88843
Busch, Martin; Herzmann, Christian; Kallert, Stephanie et al. (2016) Lipoarabinomannan-Responsive Polycytotoxic T Cells Are Associated with Protection in Human Tuberculosis. Am J Respir Crit Care Med 194:345-55
Meller, Stephan; Di Domizio, Jeremy; Voo, Kui S et al. (2015) T(H)17 cells promote microbial killing and innate immune sensing of DNA via interleukin 26. Nat Immunol 16:970-9
Cappuccio, Antonio; Zollinger, Raphaël; Schenk, Mirjam et al. (2015) Combinatorial code governing cellular responses to complex stimuli. Nat Commun 6:6847
Teles, Rosane M B; Kelly-Scumpia, Kindra M; Sarno, Euzenir N et al. (2015) IL-27 Suppresses Antimicrobial Activity in Human Leprosy. J Invest Dermatol 135:2410-2417

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