scholarly journals Granzyme-Mediated Regulation of Host Defense in the Liver in Experimental Leishmania donovani Infection

2014 ◽  
Vol 83 (2) ◽  
pp. 702-712 ◽  
Author(s):  
Henry W. Murray ◽  
Marisa Mitchell-Flack ◽  
Hua Zheng ◽  
Xiaojing Ma
Keyword(s):  
Host Defense ◽  
Leishmania Donovani ◽  
Early Stage ◽  
Acquired Resistance ◽  
Double Knockout ◽  
Th1 Cell ◽  
Content Type ◽  
Infected Liver ◽  
Parasite Replication ◽  
Cell Effector Function

In the livers of susceptible C57BL/6 (B6) mice infected withLeishmania donovani, CD8+T cell mechanisms are required for granuloma assembly, macrophage activation, intracellular parasite killing, and self-cure. Since gene expression of perforin and granzymes A and B (GzmA and GzmB), cytolytic proteins linked to CD8+cell effector function, was enhanced in infected liver tissue, B6 mice deficient in these granular proteins were used to gauge host defense roles. Neither perforin nor GzmA was required; however, mice deficient in GzmB (GzmB−/−, GzmB cluster−/−, and GzmA×B cluster double knockout [DKO] mice) showed both delayed granuloma assembly and initially impaired control of parasite replication. Since these two defects in B6 mice were limited to early-stage infection, innately resistant 129/Sv mice were also tested. In this genetic setting, expression of both innate and subsequent T (Th1) cell-dependent acquired resistance, including the self-cure phenotype, was entirely derailed in GzmA×B cluster DKO mice. These results, in susceptible B6 mice for GzmB and in resistant 129/Sv mice for GzmA and/or the GzmB cluster, point to granzyme-mediated host defense regulation in the liver in experimental visceral leishmaniasis.

scholarly journals Gamma Interferon-Regulated Chemokines in Leishmania donovani Infection in the Liver

2016 ◽  
Vol 85 (1) ◽  
Author(s):  
Henry W. Murray ◽  
Andrew D. Luster ◽  
Hua Zheng ◽  
Xiaojing Ma
Keyword(s):  
Leishmania Donovani ◽  
Mononuclear Cells ◽  
Early Stage ◽  
Granulomatous Inflammation ◽  
Gamma Interferon ◽  
Content Type ◽  
Cell Recruitment ◽  
Initial Control ◽  
Parasite Replication ◽  
Ifn Γ

ABSTRACT In the livers of C57BL/6 mice, gamma interferon (IFN-γ) controls intracellular Leishmania donovani infection and the efficacy of antimony (Sb) chemotherapy. Since both responses usually correlate with granulomatous inflammation, we tested six prominently expressed, IFN-γ-regulated chemokines—CXCL9, CXCL10, CXCL13, CXCL16, CCL2, and CCL5—for their roles in (i) mononuclear cell recruitment and granuloma assembly and maturation, (ii) initial control of infection and self-cure, and (iii) responsiveness to Sb treatment. Together, the results for the L. donovani-infected livers of chemokine-deficient mice (CXCR6−/− mice were used as CXCL16-deficient surrogates) indicated that individual IFN-γ-induced chemokines have diverse affects and (i) may be entirely dispensable (CXCL13, CXCL16), (ii) may promote (CXCL10, CCL2, CCL5) or downregulate (CXCL9) initial granuloma assembly, (iii) may enhance (CCL2, CCL5) or hinder (CXCL10) early parasite control, (iv) may promote granuloma maturation (CCL2, CCL5), (v) may exert a granuloma-independent action that enables self-cure (CCL5), and (vi) may have no role in responsiveness to chemotherapy. Despite the near absence of tissue inflammation in early-stage infection, parasite replication could be controlled (in CXCL10−/− mice) and Sb was fully active (in CXCL10−/−, CCL2−/−, and CCL5−/− mice). These results characterize chemokine action in the response to L. donovani and also reemphasize that (i) recruited mononuclear cells and granulomas are not required to control infection or respond to Sb chemotherapy, (ii) granuloma assembly, control of infection, and Sb's efficacy are not invariably linked expressions of the same T cell-dependent, cytokine-mediated antileishmanial mechanism, and (iii) granulomas are not necessarily hallmarks of protective antileishmanial immunity.

scholarly journals Guanylate Binding Proteins Restrict Leishmania donovani Growth in Nonphagocytic Cells Independent of Parasitophorous Vacuolar Targeting

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Arun Kumar Haldar ◽  
Utsav Nigam ◽  
Masahiro Yamamoto ◽  
Jörn Coers ◽  
Neena Goyal
Keyword(s):  
Host Defense ◽  
Leishmania Donovani ◽  
Binding Proteins ◽  
Critical Role ◽  
Intrinsic Property ◽  
Epithelial Cell Line ◽  
Cell Type ◽  
Phagocytic Cells ◽  
Defense Proteins ◽  
Content Type

ABSTRACT Interferon (IFN)-inducible guanylate binding proteins (GBPs) play important roles in host defense against many intracellular pathogens that reside within pathogen-containing vacuoles (PVs). For instance, members of the GBP family translocate to PVs occupied by the protozoan pathogen Toxoplasma and facilitate PV disruption and lytic parasite killing. While the GBP defense program targeting Toxoplasma has been studied in some detail, the role of GBPs in host defense to other protozoan pathogens is poorly characterized. Here, we report a critical role for both mouse and human GBPs in the cell-autonomous immune response against the vector-borne parasite Leishmania donovani. Although L. donovani can infect both phagocytic and nonphagocytic cells, it predominantly replicates inside professional phagocytes. The underlying basis for this cell type tropism is unclear. Here, we demonstrate that GBPs restrict growth of L. donovani in both mouse and human nonphagocytic cells. GBP-mediated restriction of L. donovani replication occurs via a noncanonical pathway that operates independent of detectable translocation of GBPs to L. donovan-containing vacuoles (LCVs). Instead of promoting the lytic destruction of PVs, as reported for GBP-mediated killing of Toxoplasma in phagocytic cells, GBPs facilitate the delivery of L. donovani into autolysosomal-marker-positive compartments in mouse embryonic fibroblasts as well as the human epithelial cell line A549. Together our results show that GBPs control a novel cell-autonomous host defense program, which renders nonphagocytic cells nonpermissible for efficient Leishmania replication. IMPORTANCE The obligate intracellular parasite Leishmania causes the disease leishmaniasis, which is transmitted to mammalian hosts, including humans, via the sandfly vector. Following the bite-induced breach of the skin barrier, Leishmania is known to live and replicate predominantly inside professional phagocytes. Although Leishmania is also able to infect nonphagocytic cells, nonphagocytic cells support limited parasitic replication for unknown reasons. In this study, we show that nonphagocytic cells possess an intrinsic property to restrict Leishmania growth. Our study defines a novel role for a family of host defense proteins, the guanylate binding proteins (GBPs), in antileishmanial immunity. Mechanistically, our data indicate that GBPs facilitate the delivery of Leishmania into antimicrobial autolysosomes, thereby enhancing parasite clearance in nonphagocytic cells. We propose that this GBP-dependent host defense program makes nonphagocytic cells an inhospitable host cell type for Leishmania growth.

scholarly journals PDL-1 Blockade Prevents T Cell Exhaustion, Inhibits Autophagy, and Promotes Clearance of Leishmania donovani

2018 ◽  
Vol 86 (6) ◽  
Author(s):  
Samar Habib ◽  
Abdeljabar El Andaloussi ◽  
Khaled Elmasry ◽  
Aya Handoussa ◽  
Manar Azab ◽  
...  
Keyword(s):  
T Cells ◽  
Protective Immunity ◽  
Leishmania Donovani ◽  
Parasite Burden ◽  
Parasite Clearance ◽  
Interleukin 10 ◽  
Cell Mediated Immunity ◽  
Th1 Cell ◽  
Content Type

ABSTRACT Leishmania donovani is a causative pathogen of potentially fatal visceral leishmaniasis (VL). Therapeutic agents are available; however, their use is limited because of high cost, serious side effects, and development of antimicrobial resistance. Protective immunity against VL depends on CD4 + Th1 cell-mediated immunity. Studies have shown that progression of VL is due to exhaustion of T cells; however, the mechanism involved is not clearly understood. Here, we examined the role of PD1/PDL-1 in the pathogenesis of VL by using a murine model of VL. Our data indicate that L. donovani is able to elicit initial expansion of gamma interferon-producing CD4 + Th1 and CD8 + T cells at day 7 postinfection (p.i.); however, the frequency of those cells and inflammatory response decreased at day 21 p.i., despite persistence of parasites. Persistent infection-induced expansion of interleukin-10 + FOXP3 + Treg and CD4 + and CD8 + T cells expressing PD1. Blocking of PDL-1 signaling in vivo resulted in restoration of protective type 1 responses by both CD4 + and CD8 + T cells, which resulted in a significant decrease in the parasite burden. Mechanistically, PDL-1 blocking inhibited autophagy, a cellular degradation process hijacked by Leishmania to acquire host cell nutrients for their survival. Inhibition of autophagy was marked by decreased lipidation of microtubule-associated protein 1 light chain 3, a marker of autophagosome formation, and P62 accumulation. Together, our findings show for the first time that anti-PDL-1 antibody is an effective therapeutic approach for restoration of effector arms of protective immunity against VL and subsequent parasite clearance.

scholarly journals Macrophage Microbicidal Mechanisms In Vivo: Reactive Nitrogen versus Oxygen Intermediates in the Killing of Intracellular Visceral Leishmania donovani

1999 ◽  
Vol 189 (4) ◽  
pp. 741-746 ◽  
Author(s):  
Henry W. Murray ◽  
Carl F. Nathan
Keyword(s):  
Respiratory Burst ◽  
Leishmania Donovani ◽  
Early Stage ◽  
Inflammatory Cells ◽  
Reactive Nitrogen ◽  
Oxygen Intermediates ◽  
Reactive Nitrogen Intermediates ◽  
Infected Liver ◽  
Necessary And Sufficient

To determine the relative contributions of respiratory burst–derived reactive oxygen intermediates (ROI) versus reactive nitrogen intermediates (RNI) to macrophage-mediated intracellular host defense, mice genetically deficient in these mechanisms were challenged with Leishmania donovani, a protozoan that selectively parasitizes visceral tissue macrophages. During the early stage of liver infection at wk 2, both respiratory burst–deficient gp91phox−/− (X-linked chronic granulomatous disease [X-CGD]) mice and inducible nitric oxide synthase (iNOS) knockout (KO) mice displayed comparably increased susceptibility. Thereafter, infection was unrestrained in mice lacking iNOS but was fully controlled in X-CGD mice. Mononuclear cell influx into infected liver foci in X-CGD and iNOS KO mice was also overtly impaired at wk 2. However, granuloma assembly in parasitized tissue eventually developed in both hosts but with divergent effects: mature granulomas were functionally active (leishmanicidal) in X-CGD mice but inert in iNOS-deficient animals. These results suggest that (a) ROI and RNI probably act together in the early stage of intracellular infection to regulate both tissue recruitment of mononuclear inflammatory cells and the initial extent of microbial replication, (b) RNI alone are necessary and sufficient for eventual control of visceral infection, and (c) although mature granulomas have traditionally been associated with control of such infections, these structures fail to limit intracellular parasite replication in the absence of iNOS.

scholarly journals Interleukin-10 (IL-10) in Experimental Visceral Leishmaniasis and IL-10 Receptor Blockade as Immunotherapy

2002 ◽  
Vol 70 (11) ◽  
pp. 6284-6293 ◽  
Author(s):  
Henry W. Murray ◽  
Christina M. Lu ◽  
Smita Mauze ◽  
Sherry Freeman ◽  
Andre L. Moreira ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Transgenic Mice ◽  
Leishmania Donovani ◽  
Interleukin 10 ◽  
Th1 Cell ◽  
Th1 Cytokine ◽  
Parasite Replication ◽  
High Level ◽  
Oxide Synthase ◽  
Established Infection

ABSTRACT Interleukin-10 (IL-10) is thought to promote intracellular infection, including human visceral leishmaniasis, by disabling Th1 cell-type responses and/or deactivating parasitized tissue macrophages. To develop a rationale for IL-10 inhibition as treatment in visceral infection, Th1 cytokine-driven responses were characterized in Leishmania donovani-infected BALB/c mice in which IL-10 was absent or overexpressed or its receptor (IL-10R) was blockaded. IL-10 knockout and normal mice treated prophylactically with anti-IL-10R demonstrated accelerated granuloma assembly and rapid parasite killing without untoward tissue inflammation; IL-12 and gamma interferon mRNA expression, inducible nitric oxide synthase reactivity, and responsiveness to antimony chemotherapy were also enhanced in knockout mice. In IL-10 transgenic mice, parasite replication was unrestrained, and except for antimony responsiveness, measured Th1 cell-dependent events were all initially impaired. Despite subsequent granuloma assembly, high-level infection persisted, and antimony-treated transgenic mice also relapsed. In normal mice with established infection, anti-IL-10R treatment was remarkably active, inducing near-cure by itself and synergism with antimony. IL-10's deactivating effects regulate outcome in experimental visceral leishmaniasis, and IL-10R blockade represents a potential immuno- and/or immunochemotherapeutic approach in this infection.

scholarly journals Mononuclear Cell Recruitment, Granuloma Assembly, and Response to Treatment in Experimental Visceral Leishmaniasis: Intracellular Adhesion Molecule 1-Dependent and -Independent Regulation

2000 ◽  
Vol 68 (11) ◽  
pp. 6294-6299 ◽  
Author(s):  
Henry W. Murray
Keyword(s):  
Visceral Leishmaniasis ◽  
Mononuclear Cell ◽  
Leishmania Donovani ◽  
Acquired Resistance ◽  
Tissue Response ◽  
Response To Treatment ◽  
Th1 Cell ◽  
Intracellular Adhesion Molecule ◽  
Granulomatous Tissue ◽  
High Level

ABSTRACT In experimental visceral leishmaniasis, acquired resistance to intracellular Leishmania donovani is Th1 cell cytokine dependent and largely mediated by gamma interferon (IFN-γ); the same response also permits conventional antimony (Sb) chemotherapy to express its leishmanicidal effect. Since the influxing blood monocyte (which utilizes endothelial cell ICAM-1 for adhesion and tissue entry) is a primary effector target cell for this cytokine mechanism, we tested the monocyte's role in host responsiveness to chemotherapy in mice with ICAM-1 gene disruptions. Mutant animals failed to develop any early granulomatous tissue response in the liver, initially supported high-level visceral parasite replication, and showed no killing after Sb treatment; the leishmanicidal response to a directly acting, alternative chemotherapeutic probe, amphotericin B, was intact. However, mutant mice proceeded to express a compensatory, ICAM-1-independent response leading to mononuclear cell influx and granuloma assembly, control over visceral infection, and the capacity to respond to Sb. Together, these results point to the recruitment of emigrant monocytes and mononuclear cell granuloma formation, mediated by ICAM-1-dependent and -independent pathways, as critical determinants of host responsiveness to conventional antileishmanial chemotherapy.

scholarly journals Identification of Synthetic and Natural Host Defense Peptides with Leishmanicidal Activity

2016 ◽  
Vol 60 (4) ◽  
pp. 2484-2491 ◽  
Author(s):  
A. K. Marr ◽  
S. Cen ◽  
R. E. W. Hancock ◽  
W. R. McMaster
Keyword(s):  
Host Defense ◽  
Leishmania Donovani ◽  
Leishmania Major ◽  
Public Health Problem ◽  
Major Public Health Problem ◽  
Host Defense Peptides ◽  
Content Type ◽  
Leishmanicidal Activity ◽  
Wide Range ◽  
Defense Peptides

ABSTRACTLeishmaniaparasites are a major public health problem worldwide. Effective treatment of leishmaniasis is hampered by the high incidence of adverse effects to traditional drug therapy and the emergence of resistance to current therapeutics. A vaccine is currently not available. Host defense peptides have been investigated as novel therapeutic agents against a wide range of pathogens. Here we demonstrate that the antimicrobial peptide LL-37 and the three synthetic peptides E6, L-1018, and RI-1018 exhibit leishmanicidal activity against promastigotes and intramacrophage amastigotes ofLeishmania donovaniandLeishmania major. We also report that theLeishmaniaprotease/virulence factor GP63 confers protection toLeishmaniafrom the cytolytic properties of alll-form peptides (E6, L-1018, and LL-37) but not thed-form peptide RI-1018. The results suggest that RI-1018, E6, and LL-37 are promising peptides to develop further into components for antileishmanial therapy.

scholarly journals Genomic Appraisal of the Multifactorial Basis forIn VitroAcquisition of Miltefosine Resistance in Leishmania donovani

2016 ◽  
Vol 60 (7) ◽  
pp. 4089-4100 ◽  
Author(s):  
P. Vacchina ◽  
B. Norris-Mullins ◽  
M. A. Abengózar ◽  
C. G. Viamontes ◽  
J. Sarro ◽  
...  
Keyword(s):  
Leishmania Donovani ◽  
Oral Treatment ◽  
Acquired Resistance ◽  
Severe Form ◽  
Phenotypic Traits ◽  
Infected Female ◽  
Content Type ◽  
Causative Agents ◽  
Clonal Lines

ABSTRACTProtozoan parasites of theLeishmania donovanicomplex are the causative agents of visceral leishmaniasis (VL), the most severe form of leishmaniasis, with high rates of mortality if left untreated.Leishmaniaparasites are transmitted to humans through the bite of infected female sandflies (Diptera:Phlebotominae), and approximately 500,000 new cases of VL are reported each year. In the absence of a safe human vaccine, chemotherapy, along with vector control, is the sole tool with which to fight the disease. Miltefosine (hexadecylphosphatidylcholine [HePC]), an antitumoral drug, is the only successful oral treatment for VL. In the current study, we describe the phenotypic traits ofL. donovaniclonal lines that have acquired resistance to HePC. We performed whole-genome and RNA sequencing of these resistant lines to provide an inclusive overview of the multifactorial acquisition of experimental HePC resistance, circumventing the challenge of identifying changes in membrane-bound proteins faced by proteomics. This analysis was complemented by assessment of thein vitroinfectivity of HePC-resistant parasites. Our work underscores the importance of complementary “omics” to acquire the most comprehensive insight for multifaceted processes, such as HePC resistance.

scholarly journals Visceral Leishmania donovani Infection in Interleukin-13−/− Mice

2006 ◽  
Vol 74 (4) ◽  
pp. 2487-2490 ◽  
Author(s):  
Henry W. Murray ◽  
Christine W. Tsai ◽  
Jianguo Liu ◽  
Xiaojing Ma
Keyword(s):  
Leishmania Donovani ◽  
Acquired Resistance ◽  
Gamma Interferon ◽  
Interleukin 13 ◽  
Intracellular Infection ◽  
Parasite Replication ◽  
Liver Infection

ABSTRACT Leishmania donovani-infected interleukin-13−/− BALB/c mice showed impaired initial gamma interferon secretion and incomplete granuloma assembly at parasitized liver foci. Nonetheless, control of early parasite replication, resolution of liver infection, and responsiveness to antileishmanial chemotherapy were intact. By itself, interleukin-13 does not appear to materially influence acquired resistance in this intracellular infection.

scholarly journals Loss of the Conserved Alveolate Kinase MAPK2 Decouples Toxoplasma Cell Growth from Cell Division

mBio ◽  
2020 ◽  
Vol 11 (6) ◽  
Author(s):  
Xiaoyu Hu ◽  
William J. O’Shaughnessy ◽  
Tsebaot G. Beraki ◽  
Michael L. Reese
Keyword(s):  
Toxoplasma Gondii ◽  
Protein Kinases ◽  
Daughter Cell ◽  
Protozoan Parasite ◽  
Productive Infection ◽  
Centrosome Duplication ◽  
Loss Of Function ◽  
Content Type ◽  
Mitogen Activated Protein ◽  
Parasite Replication

ABSTRACT Mitogen-activated protein kinases (MAPKs) are a conserved family of protein kinases that regulate signal transduction, proliferation, and development throughout eukaryotes. The apicomplexan parasite Toxoplasma gondii expresses three MAPKs. Two of these, extracellular signal-regulated kinase 7 (ERK7) and MAPKL1, have been implicated in the regulation of conoid biogenesis and centrosome duplication, respectively. The third kinase, MAPK2, is specific to and conserved throughout the Alveolata, although its function is unknown. We used the auxin-inducible degron system to determine phenotypes associated with MAPK2 loss of function in Toxoplasma. We observed that parasites lacking MAPK2 failed to duplicate their centrosomes and therefore did not initiate daughter cell budding, which ultimately led to parasite death. MAPK2-deficient parasites initiated but did not complete DNA replication and arrested prior to mitosis. Surprisingly, the parasites continued to grow and replicate their Golgi apparatus, mitochondria, and apicoplasts. We found that the failure in centrosome duplication is distinct from the phenotype caused by the depletion of MAPKL1. As we did not observe MAPK2 localization at the centrosome at any point in the cell cycle, our data suggest that MAPK2 regulates a process at a distal site that is required for the completion of centrosome duplication and the initiation of parasite mitosis. IMPORTANCE Toxoplasma gondii is a ubiquitous intracellular protozoan parasite that can cause severe and fatal disease in immunocompromised patients and the developing fetus. Rapid parasite replication is critical for establishing a productive infection. Here, we demonstrate that a Toxoplasma protein kinase called MAPK2 is conserved throughout the Alveolata and essential for parasite replication. We found that parasites lacking MAPK2 protein were defective in the initiation of daughter cell budding and were rendered inviable. Specifically, T. gondii MAPK2 (TgMAPK2) appears to be required for centrosome replication at the basal end of the nucleus, and its loss causes arrest early in parasite division. MAPK2 is unique to the Alveolata and not found in metazoa and likely is a critical component of an essential parasite-specific signaling network.

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