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1.
Immunology ; 156(2): 164-173, 2019 02.
Article in English | MEDLINE | ID: mdl-30357820

ABSTRACT

Macrophage (MΦ) polarization is triggered during the innate immune response to defend against microbial pathogens, but can also contribute to disease pathogenesis. In a previous study, we found that interleukin-15 (IL-15) -derived classically activated macrophages (M1 MΦ) have enhanced antimicrobial activity, whereas IL-10-derived alternatively activated macrophages (M2 MΦ) were highly phagocytic but lacked antimicrobial activity. Given that the ability to modulate MΦ polarization from M2 MΦ to M1 MΦ may promote a more effective immune response to infection, we investigated the plasticity of these MΦ programs. Addition of IL-10 to M1 MΦ induced M2-like MΦ, but IL-15 had little effect on M2 MΦ. We determined the set of immune receptors that are present on M2 MΦ, elucidating two candidates for inducing plasticity of M2 MΦ, Toll-like receptor 1 (TLR1) and interferonγ (IFN-γ) receptor 1. Stimulation of M2 MΦ with TLR2/1 ligand (TLR2/1L) or IFN-γ alone was not sufficient to alter M2 MΦ phenotype or function. However, co-addition of TLR2/1L and IFN-γ re-educated M2 MΦ towards the M1 MΦ phenotype, with a decrease in the phagocytosis of lipids and mycobacteria, as well as recovery of the vitamin-D-dependent antimicrobial pathway compared with M2 MΦ maintained in polarizing conditions. Similarly, treatment of M2 MΦ with both TLR2/1L and anti-IL-10 neutralizing antibodies led to polarization to the M1-like MΦ phenotype and function. Together, our data demonstrate an approach to induce MΦ plasticity that provides the potential for re-educating MΦ function in human mycobacterial disease to promote host defense and limit pathogenesis.


Subject(s)
Macrophage Activation , Macrophages/immunology , Mycobacterium Infections/immunology , Phagocytosis , Toll-Like Receptor 1/immunology , Toll-Like Receptor 2/immunology , Cytokines/immunology , Female , Humans , Macrophages/pathology , Male , Mycobacterium Infections/pathology , Receptors, Interferon/immunology , Interferon gamma Receptor
2.
J Immunol ; 200(9): 3244-3258, 2018 05 01.
Article in English | MEDLINE | ID: mdl-29610140

ABSTRACT

Upon recognition of a microbial pathogen, the innate and adaptive immune systems are linked to generate a cell-mediated immune response against the foreign invader. The culture filtrate of Mycobacterium tuberculosis contains ligands, such as M. tuberculosis tRNA, that activate the innate immune response and secreted Ags recognized by T cells to drive adaptive immune responses. In this study, bioinformatics analysis of gene-expression profiles derived from human PBMCs treated with distinct microbial ligands identified a mycobacterial tRNA-induced innate immune network resulting in the robust production of IL-12p70, a cytokine required to instruct an adaptive Th1 response for host defense against intracellular bacteria. As validated by functional studies, this pathway contained a feed-forward loop, whereby the early production of IL-18, type I IFNs, and IL-12p70 primed NK cells to respond to IL-18 and produce IFN-γ, enhancing further production of IL-12p70. Mechanistically, tRNA activates TLR3 and TLR8, and this synergistic induction of IL-12p70 was recapitulated by the addition of a specific TLR8 agonist with a TLR3 ligand to PBMCs. These data indicate that M. tuberculosis tRNA activates a gene network involving the integration of multiple innate signals, including types I and II IFNs, as well as distinct cell types to induce IL-12p70.


Subject(s)
Interleukin-12/immunology , Mycobacterium tuberculosis/immunology , RNA, Bacterial/immunology , RNA, Transfer/immunology , Tuberculosis/immunology , Cell Differentiation/immunology , Gene Regulatory Networks/immunology , Humans , Immunity, Cellular/immunology , Immunity, Innate/immunology , Interleukin-12/biosynthesis , Lymphocyte Activation/immunology , Receptors, Pattern Recognition/immunology , Th1 Cells/immunology
3.
PLoS Pathog ; 12(8): e1005808, 2016 08.
Article in English | MEDLINE | ID: mdl-27532668

ABSTRACT

As circulating monocytes enter the site of disease, the local microenvironment instructs their differentiation into tissue macrophages (MΦ). To identify mechanisms that regulate MΦ differentiation, we studied human leprosy as a model, since M1-type antimicrobial MΦ predominate in lesions in the self-limited form, whereas M2-type phagocytic MΦ are characteristic of the lesions in the progressive form. Using a heterotypic co-culture model, we found that unstimulated endothelial cells (EC) trigger monocytes to become M2 MΦ. However, biochemical screens identified that IFN-γ and two families of small molecules activated EC to induce monocytes to differentiate into M1 MΦ. The gene expression profiles induced in these activated EC, when overlapped with the transcriptomes of human leprosy lesions, identified Jagged1 (JAG1) as a potential regulator of MΦ differentiation. JAG1 protein was preferentially expressed in the lesions from the self-limited form of leprosy, and localized to the vascular endothelium. The ability of activated EC to induce M1 MΦ was JAG1-dependent and the addition of JAG1 to quiescent EC facilitated monocyte differentiation into M1 MΦ with antimicrobial activity against M. leprae. Our findings indicate a potential role for the IFN-γ-JAG1 axis in instructing MΦ differentiation as part of the host defense response at the site of disease in human leprosy.


Subject(s)
Cell Differentiation/physiology , Jagged-1 Protein/immunology , Leprosy/immunology , Macrophages/cytology , Coculture Techniques , Endothelial Cells/immunology , Endothelial Cells/metabolism , Humans , Immunohistochemistry , Macrophages/immunology , Microscopy, Confocal , Oligonucleotide Array Sequence Analysis , Real-Time Polymerase Chain Reaction , Transcriptome , Transfection
4.
J Virol ; 88(17): 9934-46, 2014 Sep 01.
Article in English | MEDLINE | ID: mdl-24942581

ABSTRACT

UNLABELLED: A unique aspect of human monocytes, compared to monocytes from many other species, is that they express the CD4 molecule. However, the role of the CD4 molecule in human monocyte development and function is not known. We determined that the activation of CD4 via interaction with major histocompatibility complex class II (MHC-II) triggers cytokine expression and the differentiation of human monocytes into functional mature macrophages. Importantly, we determined that CD4 activation induces intracellular signaling in monocytes and that inhibition of the MAPK and Src family kinase pathways blocked the ability of CD4 ligation to trigger macrophage differentiation. We observed that ligation of CD4 by MHC-II on activated endothelial cells induced CD4-mediated macrophage differentiation of blood monocytes. Finally, CD4 ligation by MHC-II increases the susceptibility of blood-derived monocytes to HIV binding and subsequent infection. Altogether, our studies have identified a novel function for the CD4 molecule on peripheral monocytes and suggest that a unique set of events that lead to innate immune activation differ between humans and mice. Further, these events can have effects on HIV infection and persistence in the macrophage compartment. IMPORTANCE: The CD4 molecule, as the primary receptor for HIV, plays an important role in HIV pathogenesis. There are many cell types that express CD4 other than the primary HIV target, the CD4(+) T cell. Other than allowing HIV infection, the role of the CD4 molecule on human monocytes or macrophages is not known. We were interested in determining the role of CD4 in human monocyte/macrophage development and function and the potential effects of this on HIV infection. We identified a role for the CD4 molecule in triggering the activation and development of a monocyte into a macrophage following its ligation. Activation of the monocyte through the CD4 molecule in this manner increases the ability of monocytes to bind to and become infected with HIV. Our studies have identified a novel function for the CD4 molecule on peripheral monocytes in triggering macrophage development that has direct consequences for HIV infection.


Subject(s)
CD4 Antigens/metabolism , Cell Differentiation , HIV Infections/immunology , Histocompatibility Antigens Class II/metabolism , Macrophages/physiology , Monocytes/physiology , Adult , Cytokines/metabolism , Humans , Macrophages/immunology , Monocytes/immunology , Protein Binding , Signal Transduction
5.
J Immunol ; 192(5): 2280-2290, 2014 Mar 01.
Article in English | MEDLINE | ID: mdl-24501203

ABSTRACT

A role for vitamin A in host defense against Mycobacterium tuberculosis has been suggested through epidemiological and in vitro studies; however, the mechanism is unclear. In this study, we demonstrate that vitamin A-triggered antimicrobial activity against M. tuberculosis requires expression of NPC2. Comparison of monocytes stimulated with all-trans retinoic acid (ATRA) or 1,25-dihydroxyvitamin D3 (1,25D3), the biologically active forms of vitamin A and vitamin D, respectively, indicates that ATRA and 1,25D3 induce mechanistically distinct antimicrobial activities. Stimulation of primary human monocytes with ATRA did not result in expression of the antimicrobial peptide cathelicidin, which is required for 1,25D3 antimicrobial activity. In contrast, ATRA triggered a reduction in the total cellular cholesterol concentration, whereas 1,25D3 did not. Blocking ATRA-induced cellular cholesterol reduction inhibits antimicrobial activity as well. Bioinformatic analysis of ATRA- and 1,25D3-induced gene profiles suggests that NPC2 is a key gene in ATRA-induced cholesterol regulation. Knockdown experiments demonstrate that ATRA-mediated decrease in total cellular cholesterol content and increase in lysosomal acidification are both dependent upon expression of NPC2. Expression of NPC2 was lower in caseous tuberculosis granulomas and M. tuberculosis-infected monocytes compared with normal lung and uninfected cells, respectively. Loss of NPC2 expression ablated ATRA-induced antimicrobial activity. Taken together, these results suggest that the vitamin A-mediated antimicrobial mechanism against M. tuberculosis requires NPC2-dependent expression and function, indicating a key role for cellular cholesterol regulation in the innate immune response.


Subject(s)
Antineoplastic Agents/pharmacology , Carrier Proteins/immunology , Glycoproteins/immunology , Monocytes/immunology , Mycobacterium tuberculosis/immunology , Tretinoin/pharmacology , Tuberculosis, Pulmonary/immunology , Calcitriol/pharmacology , Cholesterol/immunology , Female , Humans , Immunity, Innate , Lysosomes/immunology , Male , Monocytes/microbiology , Tuberculosis, Pulmonary/drug therapy , Tuberculosis, Pulmonary/pathology , Vesicular Transport Proteins , Vitamins/pharmacology
6.
Immunology ; 141(2): 174-80, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24032597

ABSTRACT

The rapid differentiation of monocytes into macrophages (MΦ) and dendritic cells is a pivotal aspect of the innate immune response. Differentiation is triggered following recognition of microbial ligands that activate pattern recognition receptors or directly by pro-inflammatory cytokines. We demonstrate that interleukin-1ß (IL-1ß) induces the rapid differentiation of monocytes into CD209(+) MΦ, similar to activation via Toll-like receptor 2/1, but with distinct phenotypic and functional characteristics. The IL-1ß induced MΦ express higher levels of key markers of phagocytosis, including the Fc-receptors CD16 and CD64, as well as CD36, CD163 and CD206. In addition, IL-1ß-induced MΦ exert potent phagocytic activity towards inert particles, oxidized low-density lipoprotein and mycobacteria. Furthermore, IL-1ß-induced MΦ express higher levels of HLA-DR and effectively present mycobacterial antigens to T cells. Therefore, the ability of IL-1ß to induce monocyte differentiation into MΦ with both phagocytosis and antigen-presenting function is a distinct part of the innate immune response in host defence against microbial infection.


Subject(s)
Antigen Presentation , Antigens, Bacterial/immunology , Cell Differentiation/drug effects , Interleukin-1beta/pharmacology , Macrophages/drug effects , Mycobacterium tuberculosis/immunology , T-Lymphocytes/immunology , Cell Adhesion Molecules/analysis , Humans , Lectins, C-Type/analysis , Macrophages/cytology , Macrophages/physiology , Monocytes/cytology , Phagocytosis , Receptors, Cell Surface/analysis , Toll-Like Receptor 2/physiology
7.
J Invest Dermatol ; 134(2): 381-388, 2014 Feb.
Article in English | MEDLINE | ID: mdl-23884315

ABSTRACT

Propionibacterium acnes induction of inflammatory responses is a major etiological factor contributing to the pathogenesis of acne vulgaris. In particular, the IL-1 family of cytokines has a critical role in both initiation of acne lesions and in the inflammatory response in acne. In this study, we demonstrated that human monocytes respond to P. acnes and secrete mature IL-1ß partially via the NLRP3-mediated pathway. When monocytes were stimulated with live P. acnes, caspase-1 and caspase-5 gene expression was upregulated; however, IL-1ß secretion required only caspase-1 activity. P. acnes induced key inflammasome genes including NLRP1 and NLPR3. Moreover, silencing of NLRP3, but not NLRP1, expression by small interfering RNA attenuated P. acnes-induced IL-1ß secretion. The mechanism of P. acnes-induced NLRP3 activation and subsequent IL-1ß secretion was found to involve potassium efflux. Finally, in acne lesions, mature caspase-1 and NLRP3 were detected around the pilosebaceous follicles and colocalized with tissue macrophages. Taken together, our results indicate that P. acnes triggers a key inflammatory mediator, IL-1ß, via NLRP3 and caspase-1 activation, suggesting a role for inflammasome-mediated inflammation in acne pathogenesis.


Subject(s)
Carrier Proteins/immunology , Gram-Positive Bacterial Infections/immunology , Interleukin-1beta/immunology , Monocytes/immunology , Monocytes/microbiology , Propionibacterium acnes/immunology , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/immunology , Adaptor Proteins, Signal Transducing/metabolism , Apoptosis Regulatory Proteins/genetics , Apoptosis Regulatory Proteins/immunology , Apoptosis Regulatory Proteins/metabolism , Carrier Proteins/genetics , Carrier Proteins/metabolism , Caspase 1/genetics , Caspase 1/metabolism , Caspases/genetics , Caspases/metabolism , Cells, Cultured , Humans , Inflammasomes/genetics , Inflammasomes/immunology , Inflammasomes/metabolism , Interleukin-1beta/metabolism , Macrophages/cytology , Macrophages/immunology , Macrophages/microbiology , Monocytes/cytology , NLR Family, Pyrin Domain-Containing 3 Protein , NLR Proteins , RNA, Small Interfering/genetics
8.
J Invest Dermatol ; 134(2): 366-373, 2014 Feb.
Article in English | MEDLINE | ID: mdl-23924903

ABSTRACT

Acne vulgaris is the most common skin disorder affecting millions of people worldwide and inflammation resulting from the immune response targeting Propionibacterium acnes has a significant role in its pathogenesis. In this study, we have demonstrated that P. acnes is a potent inducer of T helper 17 (Th17) and Th1, but not Th2 responses in human peripheral blood mononuclear cells (PBMCs). P. acnes stimulated expression of key Th17-related genes, including IL-17A, RORα, RORc, IL-17RA, and IL-17RC, and triggered IL-17 secretion from CD4(+), but not from CD8(+) T cells. Supernatants from P. acnes-stimulated PBMCs were sufficient to promote the differentiation of naive CD4(+)CD45RA T cells into Th17 cells. Furthermore, we found that the combination of IL-1ß, IL-6, and transforming growth factor-ß-neutralizing antibodies completely inhibited P. acnes-induced IL-17 production. Importantly, we showed that IL-17-expressing cells were present in skin biopsies from acne patients but not from normal donors. Finally, vitamin A (all-trans retinoic acid) and vitamin D (1,25-dihydroxyvitamin D3) inhibited P. acnes-induced Th17 differentiation. Together, our data demonstrate that IL-17 is induced by P. acnes and expressed in acne lesions and that both vitamin A and D could be effective tools to modulate Th17-mediated diseases such as acne.


Subject(s)
Acne Vulgaris/immunology , Gram-Positive Bacterial Infections/immunology , Interleukin-17/immunology , Propionibacterium acnes/immunology , Vitamin A/metabolism , Vitamin D/immunology , Acne Vulgaris/microbiology , Acne Vulgaris/pathology , CD4-Positive T-Lymphocytes/cytology , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/microbiology , Cell Differentiation/immunology , Gram-Positive Bacterial Infections/pathology , Humans , Interleukin-17/metabolism , Interleukins/immunology , Interleukins/metabolism , Nuclear Receptor Subfamily 1, Group F, Member 1/immunology , Nuclear Receptor Subfamily 1, Group F, Member 1/metabolism , Nuclear Receptor Subfamily 1, Group F, Member 3/immunology , Nuclear Receptor Subfamily 1, Group F, Member 3/metabolism , Receptors, Interleukin/immunology , Receptors, Interleukin/metabolism , Receptors, Interleukin-17/immunology , Receptors, Interleukin-17/metabolism , Th1 Cells/cytology , Th1 Cells/immunology , Th1 Cells/microbiology , Th17 Cells/cytology , Th17 Cells/immunology , Th17 Cells/microbiology , Interleukin-22
9.
Science ; 339(6126): 1448-53, 2013 Mar 22.
Article in English | MEDLINE | ID: mdl-23449998

ABSTRACT

Type I interferons (IFN-α and IFN-ß) are important for protection against many viral infections, whereas type II interferon (IFN-γ) is essential for host defense against some bacterial and parasitic pathogens. Study of IFN responses in human leprosy revealed an inverse correlation between IFN-ß and IFN-γ gene expression programs. IFN-γ and its downstream vitamin D-dependent antimicrobial genes were preferentially expressed in self-healing tuberculoid lesions and mediated antimicrobial activity against the pathogen Mycobacterium leprae in vitro. In contrast, IFN-ß and its downstream genes, including interleukin-10 (IL-10), were induced in monocytes by M. leprae in vitro and preferentially expressed in disseminated and progressive lepromatous lesions. The IFN-γ-induced macrophage vitamin D-dependent antimicrobial peptide response was inhibited by IFN-ß and by IL-10, suggesting that the differential production of IFNs contributes to protection versus pathogenesis in some human bacterial infections.


Subject(s)
Interferon-beta/immunology , Interferon-gamma/immunology , Leprosy, Lepromatous/immunology , Leprosy, Tuberculoid/immunology , Mycobacterium leprae/immunology , 25-Hydroxyvitamin D3 1-alpha-Hydroxylase/genetics , 25-Hydroxyvitamin D3 1-alpha-Hydroxylase/metabolism , Antimicrobial Cationic Peptides/genetics , Antimicrobial Cationic Peptides/metabolism , Humans , Interferon-beta/genetics , Interferon-beta/metabolism , Interferon-gamma/genetics , Interferon-gamma/metabolism , Interleukin-10/genetics , Interleukin-10/metabolism , Leprosy, Lepromatous/genetics , Leprosy, Lepromatous/metabolism , Leprosy, Tuberculoid/genetics , Leprosy, Tuberculoid/metabolism , Microbial Viability , Monocytes/immunology , Monocytes/metabolism , Mycobacterium leprae/physiology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptors, Calcitriol/genetics , Receptors, Calcitriol/metabolism , Transcriptome , Tuberculosis/genetics , Tuberculosis/immunology , Up-Regulation , beta-Defensins/genetics , beta-Defensins/metabolism , Cathelicidins
10.
Immunology ; 139(1): 121-8, 2013 May.
Article in English | MEDLINE | ID: mdl-23289765

ABSTRACT

The ability of T cells to activate antimicrobial pathways in infected macrophages is essential to host defence against many intracellular pathogens. Here, we compared the ability of two T-cell-mediated mechanisms to trigger antimicrobial responses against Mycobacterium tuberculosis in humans, CD40 activation and the release of interferon-γ (IFN-γ). Given that IFN-γ activates a vitamin D-dependent antimicrobial response, we focused on induction of the key components of this pathway. We show that activation of human monocytes via CD40 ligand (CD40L) and IFN-γ, alone, and in combination, induces the CYP27b1-hydroxylase, responsible for the conversion of 25-hydroxyvitamin D (25D) to the bioactive 1,25-dihydroxyvitamin D (1,25D), and the vitamin D receptor (VDR). The activation of the vitamin D pathway by CD40L and IFN-γ results in up-regulated expression of the antimicrobial peptides, cathelicidin and DEFB4, as well as induction of autophagy. Finally, activation of monocytes via CD40L and IFN-γ results in an antimicrobial activity against intracellular M. tuberculosis. Our data suggest that at least two parallel T-cell-mediated mechanisms, CD40L and IFN-γ, activate the vitamin D-dependent antimicrobial pathway and trigger antimicrobial activity against intracellular M. tuberculosis, thereby contributing to human host defence against intracellular infection.


Subject(s)
CD40 Ligand/immunology , Interferon-gamma/immunology , Monocytes/immunology , Mycobacterium tuberculosis/immunology , Receptors, Calcitriol/immunology , Tuberculosis/immunology , 25-Hydroxyvitamin D3 1-alpha-Hydroxylase/immunology , Antimicrobial Cationic Peptides/immunology , CD40 Ligand/agonists , CD40 Ligand/metabolism , Calcitriol/immunology , Female , Humans , Interferon-gamma/agonists , Interferon-gamma/metabolism , Male , Monocytes/microbiology , T-Lymphocytes/immunology , beta-Defensins/immunology , Cathelicidins
11.
J Infect Dis ; 207(6): 947-56, 2013 Mar 15.
Article in English | MEDLINE | ID: mdl-23255567

ABSTRACT

Galectin-3 is a ß-galactoside-binding lectin widely expressed on epithelial and hematopoietic cells, and its expression is frequently associated with a poor prognosis in cancer. Because it has not been well-studied in human infectious disease, we examined galectin-3 expression in mycobacterial infection by studying leprosy, an intracellular infection caused by Mycobacterium leprae. Galectin-3 was highly expressed on macrophages in lesions of patients with the clinically progressive lepromatous form of leprosy; in contrast, galectin-3 was almost undetectable in self-limited tuberculoid lesions. We investigated the potential function of galectin-3 in cell-mediated immunity using peripheral blood monocytes. Galectin-3 enhanced monocyte interleukin 10 production to a TLR2/1 ligand, whereas interleukin 12p40 secretion was unaffected. Furthermore, galectin-3 diminished monocyte to dendritic cell differentiation and T-cell antigen presentation. These data demonstrate an association of galectin-3 with unfavorable host response in leprosy and a potential mechanism for impaired host defense in humans.


Subject(s)
Galectin 3/pharmacology , Leprosy, Lepromatous/immunology , Leprosy, Tuberculoid/immunology , Monocytes/metabolism , Antigen Presentation/drug effects , Antigens, CD1/metabolism , Cell Differentiation/drug effects , Galectin 3/genetics , Galectin 3/metabolism , Gene Expression , Humans , Immunity, Cellular , Immunity, Innate , Interleukin-10/metabolism , Interleukin-12 Subunit p40/metabolism , Leprosy, Lepromatous/metabolism , Leprosy, Tuberculoid/metabolism , Macrophages/metabolism , Monocytes/drug effects , Mycobacterium leprae , RNA, Messenger/metabolism
12.
Nat Med ; 18(4): 555-63, 2012 Mar 25.
Article in English | MEDLINE | ID: mdl-22447076

ABSTRACT

It is unclear whether the ability of the innate immune system to recognize distinct ligands from a single microbial pathogen via multiple pattern recognition receptors (PRRs) triggers common pathways or differentially triggers specific host responses. In the human mycobacterial infection leprosy, we found that activation of monocytes via nucleotide-binding oligomerization domain-containing protein 2 (NOD2) by its ligand muramyl dipeptide, as compared to activation via heterodimeric Toll-like receptor 2 and Toll-like receptor 1 (TLR2/1) by triacylated lipopeptide, preferentially induced differentiation into dendritic cells (DCs), which was dependent on a previously unknown interleukin-32 (IL-32)-dependent mechanism. Notably, IL-32 was sufficient to induce monocytes to rapidly differentiate into DCs, which were more efficient than granulocyte-macrophage colony-stimulating factor (GM-CSF)-derived DCs in presenting antigen to major histocompatibility complex (MHC) class I-restricted CD8(+) T cells. Expression of NOD2 and IL-32 and the frequency of CD1b(+) DCs at the site of leprosy infection correlated with the clinical presentation; they were greater in patients with limited as compared to progressive disease. The addition of recombinant IL-32 restored NOD2-induced DC differentiation in patients with the progressive form of leprosy. In conclusion, the NOD2 ligand-induced, IL-32-dependent DC differentiation pathway contributes a key and specific mechanism for host defense against microbial infection in humans.


Subject(s)
Dendritic Cells/metabolism , Interleukins/metabolism , Leprosy/pathology , Nod2 Signaling Adaptor Protein/metabolism , Antigens, CD , CD11b Antigen , Cell Differentiation/drug effects , Cytokines/genetics , Cytokines/metabolism , Dendritic Cells/drug effects , Dose-Response Relationship, Drug , Enzyme-Linked Immunosorbent Assay , Gene Expression Profiling , Gene Expression Regulation/physiology , Granulocyte-Macrophage Colony-Stimulating Factor/genetics , Granulocyte-Macrophage Colony-Stimulating Factor/metabolism , Granulocyte-Macrophage Colony-Stimulating Factor/pharmacology , Humans , Interleukins/pharmacology , Ligands , Macrophage Migration-Inhibitory Factors/metabolism , Oligonucleotide Array Sequence Analysis , Principal Component Analysis , RNA, Messenger/metabolism , Receptors, Granulocyte-Macrophage Colony-Stimulating Factor/genetics , Receptors, Granulocyte-Macrophage Colony-Stimulating Factor/metabolism
13.
Sci Transl Med ; 3(104): 104ra102, 2011 Oct 12.
Article in English | MEDLINE | ID: mdl-21998409

ABSTRACT

Control of tuberculosis worldwide depends on our understanding of human immune mechanisms, which combat the infection. Acquired T cell responses are critical for host defense against microbial pathogens, yet the mechanisms by which they act in humans remain unclear. We report that T cells, by the release of interferon-γ (IFN-γ), induce autophagy, phagosomal maturation, the production of antimicrobial peptides such as cathelicidin, and antimicrobial activity against Mycobacterium tuberculosis in human macrophages via a vitamin D-dependent pathway. IFN-γ induced the antimicrobial pathway in human macrophages cultured in vitamin D-sufficient sera, but not in sera from African-Americans that have lower amounts of vitamin D and who are more susceptible to tuberculosis. In vitro supplementation of vitamin D-deficient serum with 25-hydroxyvitamin D3 restored IFN-γ-induced antimicrobial peptide expression, autophagy, phagosome-lysosome fusion, and antimicrobial activity. These results suggest a mechanism in which vitamin D is required for acquired immunity to overcome the ability of intracellular pathogens to evade macrophage-mediated antimicrobial responses. The present findings underscore the importance of adequate amounts of vitamin D in all human populations for sustaining both innate and acquired immunity against infection.


Subject(s)
Anti-Infective Agents/pharmacology , Interferon-gamma/metabolism , Macrophages/drug effects , Vitamin D/metabolism , Antimicrobial Cationic Peptides/chemistry , Autophagy , Calcifediol/blood , Humans , Lymphocyte Activation , Macrophages/cytology , Macrophages/metabolism , Models, Biological , Monocytes/cytology , Mycobacterium tuberculosis/metabolism , Tuberculosis/microbiology
14.
Proc Natl Acad Sci U S A ; 107(52): 22593-8, 2010 Dec 28.
Article in English | MEDLINE | ID: mdl-21149724

ABSTRACT

We investigated the mechanisms by which T-cell cytokines are able to influence the Toll-like receptor (TLR)-induced, vitamin D-dependent antimicrobial pathway in human monocytes. T-cell cytokines differentially influenced TLR2/1-induced expression of the antimicrobial peptides cathelicidin and DEFB4, being up-regulated by IFN-γ, down-regulated by IL-4, and unaffected by IL-17. The Th1 cytokine IFN-γ up-regulated TLR2/1 induction of 25-hydroxyvitamin D-1α-hydroxylase (i.e., CYP27B1), leading to enhanced bioconversion of 25-hydroxyvitamin D(3) (25D(3)) to its active metabolite 1,25D(3). In contrast, the Th2 cytokine IL-4, by itself and in combination with the TLR2/1 ligand, induced catabolism of 25D(3) to the inactive metabolite 24,25D(3), and was dependent on expression of vitamin D-24-hydroxylase (i.e., CYP24A1). Therefore, the ability of T-cell cytokines to differentially control monocyte vitamin D metabolism represents a mechanism by which cell-mediated immune responses can regulate innate immune mechanisms to defend against microbial pathogens.


Subject(s)
Antimicrobial Cationic Peptides/metabolism , Cytokines/pharmacology , Monocytes/drug effects , Vitamin D/metabolism , 25-Hydroxyvitamin D3 1-alpha-Hydroxylase/genetics , 25-Hydroxyvitamin D3 1-alpha-Hydroxylase/metabolism , Antimicrobial Cationic Peptides/genetics , Blotting, Western , Calcitriol/metabolism , Cells, Cultured , Gene Expression/drug effects , Humans , Interferon-gamma/pharmacology , Interleukin-4/pharmacology , Monocytes/cytology , Monocytes/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction/drug effects , Steroid Hydroxylases/genetics , Steroid Hydroxylases/metabolism , T-Lymphocytes/metabolism , Th1 Cells/metabolism , Th2 Cells/metabolism , Toll-Like Receptor 1/metabolism , Toll-Like Receptor 2/metabolism , Vitamin D/analogs & derivatives , Vitamin D3 24-Hydroxylase , beta-Defensins/genetics , beta-Defensins/metabolism , Cathelicidins
15.
Infect Immun ; 78(11): 4634-43, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20713631

ABSTRACT

The ability of microbial pathogens to target specific cell types is a key aspect of the pathogenesis of infectious disease. Mycobacterium leprae, by infecting Schwann cells, contributes to nerve injury in patients with leprosy. Here, we investigated mechanisms of host-pathogen interaction in the peripheral nerve lesions of leprosy. We found that the expression of the C-type lectin, CD209, known to be expressed on tissue macrophages and to mediate the uptake of M. leprae, was present on Schwann cells, colocalizing with the Schwann cell marker, CNPase (2',3'-cyclic nucleotide 3'-phosphodiesterase), along with the M. leprae antigen PGL-1 in the peripheral nerve biopsy specimens. In vitro, human CD209-positive Schwann cells, both from primary cultures and a long-term line, have a higher binding of M. leprae compared to CD209-negative Schwann cells. Interleukin-4, known to be expressed in skin lesions from multibacillary patients, increased CD209 expression on human Schwann cells and subsequent Schwann cell binding to M. leprae, whereas Th1 cytokines did not induce CD209 expression on these cells. Therefore, the regulated expression of CD209 represents a common mechanism by which Schwann cells and macrophages bind and take up M. leprae, contributing to the pathogenesis of leprosy.


Subject(s)
Cell Adhesion Molecules/metabolism , Host-Pathogen Interactions , Interleukin-4/metabolism , Lectins, C-Type/metabolism , Leprosy, Tuberculoid/pathology , Mycobacterium leprae/physiology , Receptors, Cell Surface/metabolism , Schwann Cells/microbiology , Cell Line, Tumor , Humans , Interleukin-4/immunology , Leprosy, Tuberculoid/immunology , Leprosy, Tuberculoid/microbiology , Mycobacterium leprae/pathogenicity , Schwann Cells/immunology , Schwann Cells/metabolism , Schwann Cells/pathology , Up-Regulation
16.
Cell Host Microbe ; 6(4): 343-53, 2009 Oct 22.
Article in English | MEDLINE | ID: mdl-19837374

ABSTRACT

Effective innate immunity against many microbial pathogens requires macrophage programs that upregulate phagocytosis and direct antimicrobial pathways, two functions generally assumed to be coordinately regulated. We investigated the regulation of these key functions in human blood-derived macrophages. Interleukin-10 (IL-10) induced the phagocytic pathway, including the C-type lectin CD209 and scavenger receptors, resulting in phagocytosis of mycobacteria and oxidized low-density lipoprotein. IL-15 induced the vitamin D-dependent antimicrobial pathway and CD209, yet the cells were less phagocytic. The differential regulation of macrophage functional programs was confirmed by analysis of leprosy lesions: the macrophage phagocytosis pathway was prominent in the clinically progressive, multibacillary form of the disease, whereas the vitamin D-dependent antimicrobial pathway predominated in the self-limited form and in patients undergoing reversal reactions from the multibacillary to the self-limited form. These data indicate that macrophage programs for phagocytosis and antimicrobial responses are distinct and differentially regulated in innate immunity to bacterial infections.


Subject(s)
Leprosy/immunology , Macrophages/immunology , Microbial Viability , Mycobacterium leprae/immunology , Mycobacterium leprae/physiology , Phagocytosis , Gene Expression Profiling , Gene Expression Regulation , Humans , Interleukin-10/immunology , Interleukin-15/immunology
17.
J Immunol ; 183(4): 2349-55, 2009 Aug 15.
Article in English | MEDLINE | ID: mdl-19635920

ABSTRACT

The formation of immune complexes results in activation of the innate immune system and subsequent induction of host inflammatory responses. In particular, the binding of IgG immune complexes to FcgammaR on monocytes triggers potent inflammatory responses leading to tissue injury in disease. We investigated whether activation of monocytes via FcgammaR induced cell differentiation, imparting specific inflammatory functions of the innate immune response. Human IgG alone induced monocytes to differentiate into cells with an immature dendritic cell (iDC) phenotype, including up-regulation of CD1b, CD80, CD86, and CD206. Differentiation into CD1b(+) iDC was dependent on activation via CD64 (FcgammaRI) and induction of GM-CSF. The human IgG-differentiated iDC were phenotypically different from GM-CSF-derived iDC at the same level of CD1b expression, with higher cell surface CD86, but lower MHC class II, CD32, CD206, and CD14. Finally, in comparison to GM-CSF-derived iDC, IgG-differentiated iDC were more efficient in activating T cells in both autologous and allogeneic mixed lymphocyte reactions but less efficient at presenting microbial Ag to T cells. Therefore, activation of FcgammaRI on monocytes triggers differentiation into specialized iDC with the capacity to expand autoreactive T cells that may contribute to the pathogenesis of immune complex-mediated tissue injury.


Subject(s)
Autoimmune Diseases/immunology , Cell Differentiation/immunology , Dendritic Cells/immunology , Dendritic Cells/metabolism , Monocytes/immunology , Receptors, IgG/blood , T-Lymphocyte Subsets/immunology , Antigens, CD1/biosynthesis , Antigens, CD1/genetics , Autoimmune Diseases/blood , Autoimmune Diseases/pathology , Cell Adhesion Molecules/metabolism , Cell Differentiation/genetics , Cells, Cultured , Dendritic Cells/pathology , Granulocyte-Macrophage Colony-Stimulating Factor/physiology , Humans , Immune Complex Diseases/blood , Immune Complex Diseases/immunology , Immune Complex Diseases/pathology , Inflammation Mediators/blood , Inflammation Mediators/physiology , Lectins, C-Type/metabolism , Lymphocyte Activation/genetics , Lymphocyte Activation/immunology , Monocytes/cytology , Monocytes/metabolism , Receptors, Cell Surface/metabolism , Receptors, IgG/biosynthesis , Receptors, IgG/genetics , T-Lymphocyte Subsets/metabolism , T-Lymphocyte Subsets/pathology
18.
J Immunol ; 181(10): 7115-20, 2008 Nov 15.
Article in English | MEDLINE | ID: mdl-18981132

ABSTRACT

An essential function of the innate immune system is to directly trigger antimicrobial mechanisms to defend against invading pathogens. In humans, one such pathway involves activation by TLR2/1L leading to the vitamin D-dependent induction of antimicrobial peptides. In this study, we found that TLR2/1-induced IL-15 was required for induction of CYP27b1, the VDR and the downstream antimicrobial peptide cathelicidin. Although both IL-15 and IL-4 triggered macrophage differentiation, only IL-15 was sufficient by itself to induce CYP27b1 and subsequent bioconversion of 25-hydroxyvitamin D3 (25D3) into bioactive 1,25D3, leading to VDR activation and induction of cathelicidin. Finally, IL-15-differentiated macrophages could be triggered by 25D3 to induce an antimicrobial activity against intracellular Mycobacterium tuberculosis. Therefore, IL-15 links TLR2/1-induced macrophage differentiation to the vitamin D-dependent antimicrobial pathway.


Subject(s)
Cell Differentiation/immunology , Interleukin-15/metabolism , Macrophages/cytology , Toll-Like Receptor 1/metabolism , Toll-Like Receptor 2/metabolism , Vitamin D/metabolism , 25-Hydroxyvitamin D3 1-alpha-Hydroxylase/immunology , 25-Hydroxyvitamin D3 1-alpha-Hydroxylase/metabolism , Antimicrobial Cationic Peptides/immunology , Antimicrobial Cationic Peptides/metabolism , Gene Expression , Humans , Interleukin-15/immunology , Macrophages/microbiology , Macrophages/physiology , Receptors, Calcitriol/immunology , Receptors, Calcitriol/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Toll-Like Receptor 1/immunology , Toll-Like Receptor 2/immunology , Vitamin D/immunology , Cathelicidins
19.
J Immunol ; 180(9): 5833-42, 2008 May 01.
Article in English | MEDLINE | ID: mdl-18424702

ABSTRACT

CD4(+) T cell clones derived from a leprosy lesion and patient blood were used to monitor the isolation and identification of an Ag associated with the self-limited form of the disease. Biochemical purification and genetic analysis identified the T cell Ag as a conserved mycobacterial lipoglycoprotein LprG. LprG-mediated activation of CD4(+) T cells required specific MHC class II restriction molecules and intracellular processing. Although LprG activated TLR2, this alone was not sufficient to stimulate or inhibit T cell activation. A striking finding was that the carbohydrate moieties of LprG were required for optimal T cell activation, because recombinant LprG produced in Escherichia coli, or recombinant LprG produced in Mycobacterium smegmatis and digested by alpha-mannosidase, did not activate T cells. This study demonstrates that the universe of bacterial T cell Ags includes lipoglycoproteins, which act as TLR2 ligands but also require glycosylation for MHC class II-restricted T cell activation in vivo.


Subject(s)
Antigens, Bacterial/immunology , CD4-Positive T-Lymphocytes/immunology , Histocompatibility Antigens Class II/immunology , Lipoproteins/immunology , Mycobacterium/immunology , Toll-Like Receptor 2/immunology , Antigens, Bacterial/genetics , Carbohydrates/chemistry , Carbohydrates/genetics , Carbohydrates/immunology , Escherichia coli/genetics , Escherichia coli/immunology , Humans , Lipoproteins/genetics , Lymphocyte Activation/physiology , Mycobacterium/genetics , Recombinant Proteins/genetics , Recombinant Proteins/immunology , alpha-Mannosidase/chemistry
20.
J Immunol ; 180(7): 4919-23, 2008 Apr 01.
Article in English | MEDLINE | ID: mdl-18354216

ABSTRACT

Propionibacterium acnes is a major etiological factor of acne, triggering an inflammatory response in part through the activation of TLR2. In this study, we demonstrate that activation of peripheral blood monocytes with P. acnes in vitro induced their differentiation into two distinct innate immune cell subsets, CD209(+) macrophages and CD1b(+) dendritic cells. Furthermore, P. acnes induced expression of mRNA for the cytokines IL-15 and GM-CSF, which differentiate CD209(+) and CD1b(+) cells, respectively. The CD209(+) cells were more effective in uptake of P. acnes, compared with the CD1b(+) cells, and demonstrated a 2-fold greater antimicrobial activity against the phagocytosed bacteria. Although CD1b(+) cells secreted inflammatory cytokines in response to both P. acnes and a TLR2 ligand control, the CD209(+) cells responded only to P. acnes. The addition of all-trans retinoic acid, a commonly used agent for the treatment of acne, directly induced differentiation of monocytes into CD209(+) macrophages and enhanced the P. acnes-mediated differentiation of the CD209(+) subset. Therefore, the differentiation of monocytes into CD209(+) macrophages and CD1b(+) dendritic cells distinctly mediate the innate immune response to P. acnes.


Subject(s)
Cell Adhesion Molecules/immunology , Lectins, C-Type/immunology , Macrophages/immunology , Propionibacterium acnes/immunology , Receptors, Cell Surface/immunology , Antigens, CD1/immunology , Cell Differentiation/drug effects , Cells, Cultured , Cytokines/biosynthesis , Humans , Monocytes/cytology , Monocytes/drug effects , Monocytes/immunology , Tretinoin/pharmacology
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