Modulation of Splenic B Cell Subsets during Experimental Leishmania donovani Infection in BALB/c Mice.
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SUBMITTER: Mondal K
PROVIDER: S-EPMC8308600 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:IntroductionSpatial analysis of lipids in inflammatory microenvironments is key to understand the pathogenesis of infectious disease. Granulomatous inflammation is a hallmark of leishmaniasis and changes in host and parasite lipid metabolism have been observed at the bulk tissue level in various infection models. Here, mass spectrometry imaging (MSI) is applied to spatially map hepatic lipid composition following infection with Leishmania donovani, an experimental mouse model of visceral leishmaniasis.MethodsLivers from naïve and L. donovani-infected C57BL/6 mice were harvested at 14- and 20-days post-infection (n=5 per time point). 12 µm transverse sections were cut and covered with norhamane, prior to lipid analysis using MALDI-MSI. MALDI-MSI was performed in negative mode on a Rapiflex (Bruker Daltonics) at 5 and 50 µm spatial resolution and data-dependent analysis (DDA) on an Orbitrap-Elite (Thermo-Scientific) at 50 µm spatial resolution for structural identification analysis of lipids.ResultsAberrant lipid abundances were observed in a heterogeneous distribution across infected mouse livers compared to naïve mouse liver. Distinctive localized correlated lipid masses were found in granulomas and surrounding parenchymal tissue. Structural identification revealed 40 different lipids common to naïve and d14/d20 infected mouse livers, whereas 15 identified lipids were only detected in infected mouse livers. For pathology-guided MSI imaging, we deduced lipids from manually annotated granulomatous and parenchyma regions of interests (ROIs), identifying 34 lipids that showed significantly different intensities between parenchyma and granulomas across all infected livers.DiscussionOur results identify specific lipids that spatially correlate to the major histopathological feature of Leishmania donovani infection in the liver, viz. hepatic granulomas. In addition, we identified a three-fold increase in the number of unique phosphatidylglycerols (PGs) in infected liver tissue and provide direct evidence that arachidonic acid-containing phospholipids are localized with hepatic granulomas. These phospholipids may serve as important precursors for downstream oxylipin generation with consequences for the regulation of the inflammatory cascade. This study provides the first description of the use of MSI to define spatial-temporal lipid changes at local sites of infection induced by Leishmania donovani in mice.
| S-EPMC9394181 | biostudies-literature
Project description:Leishmania martiniquensis is a neglected cause of an emerging leishmaniasis in many countries, including France, Germany, Switzerland, the United States of America, Myanmar, and Thailand, with different clinical manifestations ranging from asymptomatic, cutaneous (CL), visceral (VL), and atypically disseminated CL and VL. The persistence of parasites and the recurrence of the disease after treatment are challenges in controlling the disease. To explore efficient prophylaxis and therapy, this study aimed to investigate infection outcome and organ-specific immune responses after inoculation with L. martiniquensis (MHOM/TH/2011/PG; 5 x 106 promastigotes) in BALB/c mice via intravenous and intraperitoneal routes. A quantitative PCR technique, targeting L. martiniquensis ITS1, was primarily established to estimate the parasite burden. We found that the infection in the liver resolved; however, persistent infection was observed in the spleen. Histopathology with Leishmania-specific immunostaining revealed efficient hepatic granuloma formation, while splenic disorganization with parasitized macrophages at different locations was demonstrated. The mRNA expression of Th1 cytokines (IFN-γ, TNF-α, IL-12p40) and iNOS in the liver and spleen was upregulated. In addition, high expression of IL-10 was observed in the spleen in the chronic phase, revealing a significant moderate correlation with the parasite persistence [r(12) = 0.72, P = 0.009]. Further clarification of the mechanisms of persistent infection and experimental infection in immunosuppressed murine models are warranted.
| S-EPMC8718515 | biostudies-literature
Project description:Pathophysiology of visceral leishmaniasis (VL) is not fully understood and it has been widely accepted that the parasitic components and host immune response both contribute to the perpetuation of the disease. Host alterations during leishmaniasis is a feebly touched area that needs to be explored more to better understand the VL prognosis and diagnosis, which are vital to reduce mortality and post-infection sequelae. To address this, we performed untargeted metabolomics of Leishmania donovani (Ld) infected, uninfected and treated BALB/c mice's tissues and biofluids to elucidate the host metabolome changes using gas chromatography-mass spectrometry. Univariate and multivariate data treatments provided numerous significant differential hits in several tissues like the brain, liver, spleen and bone marrow. Differential modulations were also observed in serum, urine and fecal samples of Ld-infected mice, which could be further targeted for biomarker and diagnostic validations. Several metabolic pathways were found to be upregulated/downregulated in infected (TCA, glycolysis, fatty acids, purine and pyrimidine, etcetera) and treated (arginine, fumaric acid, orotic acid, choline succinate, etcetera) samples. Results also illustrated several metabolites with different pattern of modulations in control, infected and treated samples as well as in different tissues/biofluids; for e.g. glutamic acid identified in the serum samples of infected mice. Identified metabolites include a range of amino acids, saccharides, energy-related molecules, etcetera. Furthermore, potential biomarkers have been identified in various tissues-arginine and fumaric acid in brain, choline in liver, 9-(10) EpOME in spleen and bone marrow, N-acetyl putrescine in bone marrow, etcetera. Among biofluids, glutamic acid in serum, hydrazine and deoxyribose in urine and 3-Methyl-2-oxo pentanoic acid in feces are some of the potential biomarkers identified. These metabolites could be further looked into for their role in disease complexity or as a prognostic marker. The presented profiling approach allowed us to attain a metabolic portrait of the individual tissue/biofluid modulations during VL in the host and represent a valuable system readout for further studies. Our outcomes provide an improved understanding of perturbations of the host metabolome interface during VL, including identification of many possible potential diagnostic and therapeutic targets.
| S-EPMC8358651 | biostudies-literature
Project description:Protozoa of the genus Leishmania are causative agents of leishmaniasis, an important health problem in both human and veterinary medicine. Here, we describe a new heat shock protein (HSP) in Leishmania, belonging to the small HSP (sHSP) family in kinetoplastids. The protein is highly conserved in different Leishmania species, showing instead significant divergence with sHSP's from other organisms. The humoral response elicited against this protein during Leishmania infection has been investigated in natural infected humans and dogs, and in experimentally infected hamsters. Leishmania HSP20 is a prominent antigen for canine hosts; on the contrary, the protein seems to be a poor antigen for human immune system. Time-course analysis of appearance of anti-HSP20 antibodies in golden hamsters indicated that these antibodies are produced at late stages of the infection, when clinical symptoms of disease are patent. Finally, the protective efficacy of HSP20 was assessed in mice using a DNA vaccine approach prior to challenge with Leishmania amazonensis.
| S-EPMC2288687 | biostudies-literature
Project description:BACKGROUND: In 2005 huge epizooty of H5N1 HPAI occurred in Russia. It had been clear that territory of Russia becoming endemic for H5N1 HPAI. In 2006 several outbreaks have occurred. To develop new vaccines and antiviral therapies, animal models had to be investigated. We choose highly pathogenic strain for these studies. RESULTS: A/duck/Tuva/01/06 belongs to Quinghai-like group viruses. Molecular markers-cleavage site, K627 in PB2 characterize this virus as highly pathogenic. This data was confirmed by direct pathogenic tests: IVPI = 3.0, MLD50 = 1,4Log10EID50. Also molecular analysis showed sensitivity of the virus to adamantanes and neuraminidase inhibitors. Serological analysis showed wide cross-reactivity of this virus with sera produced to H5N1 HPAI viruses isolated earlier in South-East Asia. Mean time to death of infected animals was 8,19+/-0,18 days. First time acute delayed hemorrhagic syndrome was observed in mice lethal model. Hypercytokinemia was determined by elevated sera levels of IFN-gamma, IL-6, IL-10. CONCLUSION: Assuming all obtained data we can conclude that basic model parameters were characterized and virus A/duck/Tuva/01/06 can be used to evaluate anti-influenza vaccines and therapeutics.
| S-EPMC1973068 | biostudies-literature
Project description:BACKGROUND:Leishmaniasis is a worldwide disease prevalent in tropical and sub-tropical countries in the world. Characterization of inflammatory responses produced in cutaneous leishmaniasis has not yet been completed. METHODS:The specific primers were designed for ten pro-inflammatory genes including CCL4, CCL3, TNF-?, IL-1?, IL-12P35, IL-12P40, CCL5, CCR5, IL-1? and IFN- ? and their expression were assessed and compared using RT-PCR in the lesion and peripheral blood neutrophils in Leishmania infected BALB/c mice. RESULTS:None of the pro-inflammatory genes was expressed in the healthy tissue and except IFN-? others were down-regulated by the parasite in the lesion in untreated mice. In mice treated with anti-Leishmanial drugs, the expression of the pro-inflammatory genes restarted. The figure of pro-inflammatory gene expression in neutrophils was different was from the lesions in treated and untreated mice. CONCLUSION:Leishmania is capable to suppress the expression of pro-inflammatory genes in the lesions but not in neutrophils. The expression of TNF-? in the lesions and down-regulation of IL-1? in neutrophils could be accounted as an indication for healing of cutaneous leishmaniasis. The results open a new window on characterization of Leishmania lesions and clarifying the role of neutrophils in Leishmania infections.
| S-EPMC5251182 | biostudies-literature
Project description:In the livers of susceptible C57BL/6 (B6) mice infected with Leishmania 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.
| S-EPMC4294235 | biostudies-literature
Project description:Hemophagocytosis is a phenomenon in which macrophages phagocytose blood cells. There are reports on up-regulated hemophagocytosis in patients with infectious diseases including typhoid fever, tuberculosis, influenza and visceral leishmaniasis (VL). However, mechanisms of infection-associated hemophagocytosis remained elusive due to a lack of appropriate animal models. Here, we have established a mouse model of VL with hemophagocytosis. At 24 weeks after infection with 1 x 10(7) Leishmania donovani promastigotes, BALB/cA mice exhibited splenomegaly with an average tissue weight per body weight of 2.96%. In the tissues, 28.6% of macrophages contained phagocytosed erythrocytes. All of the hemophagocytosing macrophages were parasitized by L. donovani, and higher levels of hemophagocytosis was observed in heavily infected cells. Furthermore, more than half of these hemophagocytes had two or more macrophage-derived nuclei, whereas only 15.0% of splenic macrophages were bi- or multi-nuclear. These results suggest that direct infection by L. donovani causes hyper-activation of host macrophages to engulf blood cells. To our knowledge, this is the first report on hemophagocytosis in experimental Leishmania infections and may be useful for further understanding of the pathogenesis.
| S-EPMC4778860 | biostudies-literature
Project description:The neurotrophic tyrosine kinase receptor type 2 (Ntrk2, also known as TrkB) and its ligands brain derived neurotrophic factor (Bdnf), neurotrophin-4 (NT-4/5), and neurotrophin-3 (NT-3) are known primarily for their multiple effects on neuronal differentiation and survival. Here, we provide evidence that Ntrk2 plays a role in the pathologic remodeling of the spleen that accompanies chronic infection. We show that in Leishmania donovani-infected mice, Ntrk2 is aberrantly expressed on splenic endothelial cells and that new maturing blood vessels within the white pulp are intimately associated with F4/80(hi)CD11b(lo)CD11c(+) macrophages that express Bdnf and NT-4/5 and have pro-angiogenic potential in vitro. Furthermore, administration of the small molecule Ntrk2 antagonist ANA-12 to infected mice significantly inhibited white pulp neovascularization but had no effect on red pulp vascular remodeling. We believe this to be the first evidence of the Ntrk2/neurotrophin pathway driving pathogen-induced vascular remodeling in lymphoid tissue. These studies highlight the therapeutic potential of modulating this pathway to inhibit pathological angiogenesis.
| S-EPMC4339582 | biostudies-literature
Project description:Leishmaniasis causes significant morbidity and mortality worldwide, and no vaccines against this disease are available. Previously, we had shown that the amastigote-specific protein p27 (Ldp27) is a component of an active cytochrome c oxidase complex in Leishmania donovani and that upon deletion of its gene the parasite had reduced virulence in vivo. In this study, we have shown that Ldp27(-/-) parasites do not survive beyond 20 wk in BALB/c mice and hence are safe as an immunogen. Upon virulent challenge, mice 12 wk postimmunization showed significantly lower parasite burden in the liver and spleen. When mice were challenged 20 wk postimmunization, a significant reduction in parasite burden was still noted, suggesting long-term protection by Ldp27(-/-) immunization. Immunization with Ldp27(-/-) induced both pro- and anti-inflammatory cytokine responses and activated splenocytes for enhanced leishmanicidal activity in association with NO production. Protection in both short- and long-term immunized mice after challenge with the wild-type parasite correlated with the stimulation of multifunctional Th1-type CD4 and CD8 T cells. Adoptive transfer of T cells from long-term immunized mice conferred protection against virulent challenge in naive recipient mice, suggesting involvement of memory T cell response in protection against Leishmania infection. Immunization of mice with Ldp27(-/-)also demonstrated cross-protection against Leishmania major and Leishmania braziliensis infection. Our data show that genetically modified live attenuated Ldp27(-/-) parasites are safe, induce protective immunity even in the absence of parasites, and can provide protection against homologous and heterologous Leishmania species.
| S-EPMC3578143 | biostudies-literature