Project description:The host immune response plays a critical role not only in protection from human leishmaniasis, but also in promoting disease severity. Although candidate gene approaches in mouse models of leishmaniasis have been extremely informative, a global understanding of the immune pathways active in lesions from human patients is lacking. To address this issue, genome-wide transcriptional profiling of Leishmania braziliensis-infected cutaneous lesions and normal skin controls was carried out. A signature of the L. braziliensis skin lesion was defined that includes over 2,000 differentially regulated genes. Pathway-level analysis of this transcriptional response revealed key biological pathways, as well as specific genes, associated with cutaneous pathology, generating a testable 'metapathway' model of immune-driven lesion pathology, and providing new insights for treatment of human leishmaniasis. Thirty-five skin biopsies were analyzed, including 10 normal skin biopsies (2 from North America and 8 from non-endemic area in Brazil), and 25 skin lesion biopsies (8 early cutaneous lesions, 17 late cutaneous lesions) obtained from Leishmania brazilensis-infected patients presenting at the Corte de Pedra Health Post in Corte de Pedra, Bahia, Brazil.
Project description:As a vector-borne disease, leishmaniasis is caused by a parasitic protozoans of leishmania genus and transmitted by female Phlebotomine sandflies. Depending on the body location where immotile form of the parasite namely amastigote is proliferated, three main clinical forms as cutaneous, muco-cutaneous and visceral leishmaniases are defined. While manifestation of cutaneous leishmaniasis is skin lesions on the exposed part of the body, enlarged lymph nodes, spleen or liver along with fever, fatigue and weight loss are the symptoms of visceral leishmaniasis. The most dangerous form is visceral leishmaniasis since it may end up with fatalities if patients are not treated. The purpose of this study was to investigate the difference between the protein expression profiles of leishmania isolates obtained from visceral and cutaneous leishmaniasis patients. To compare two sample groups to each other genetically, L.infantum was chosen since it causes both visceral and cutaneous leishmaniasis. Additionally, another sample group as cutaneous leishmaniasis caused by L.tropica was included to make the comparison both intra- and interspecies level. For protein profiling, both gel-based and gel-free proteomic approaches were carried out. In brief, a total of 15 samples, 5 from each group, were separated on pI 3-10 2D-PAGE gel. Additionally, 9 of those 15 samples, 3 from each group, were analyzed according to qualitative shotgun proteomics method and differential proteins were determined by drawing venn diagram.
Project description:The host immune response plays a critical role not only in protection from human leishmaniasis, but also in promoting disease severity. Although candidate gene approaches in mouse models of leishmaniasis have been extremely informative, a global understanding of the immune pathways active in lesions from human patients is lacking. To address this issue, genome-wide transcriptional profiling of Leishmania braziliensis-infected cutaneous lesions and normal skin controls was carried out. A signature of the L. braziliensis skin lesion was defined that includes over 2,000 differentially regulated genes. Pathway-level analysis of this transcriptional response revealed key biological pathways, as well as specific genes, associated with cutaneous pathology, generating a testable 'metapathway' model of immune-driven lesion pathology, and providing new insights for treatment of human leishmaniasis.
Project description:Cutaneous leishmaniasis caused by Leishmania parasites exhibits a wide range of clinical manifestations. Although parasites influence disease severity, cytolytic CD8 T cell responses mediate disease. While these responses originate in the lymph node, we found that expression of the cytolytic effector molecule granzyme B was restricted to lesional CD8 T cells in Leishmania-infected mice, suggesting that local cues within inflamed skin induced cytolytic function. Expression of Blimp-1 (Prdm1), a transcription factor necessary for cytolytic CD8 T cell differentiation, was driven by hypoxia within the inflamed skin. Hypoxia was further enhanced by the recruitment of neutrophils that consumed oxygen to produce reactive oxygen species and ultimately increased the hypoxic state and granzyme B expression in CD8 T cells. Importantly, lesions from cutaneous leishmaniasis patients exhibited hypoxia transcription signatures that correlated with the presence of neutrophils. Thus, targeting hypoxia-driven signals that support local differentiation of cytolytic CD8 T cells may improve the prognosis for patients with cutaneous leishmaniasis, as well as other inflammatory skin diseases where cytolytic CD8 T cells contribute to pathogenesis.
Project description:Leishmania RNA virus is an endosymbiotic virus of obligate intracellular Leishmania parasites. The presence of Leishmania RNA virus has been associated to metastatic leishmaniasis in hamsters and the failure of the first-line treatment in humans. This experiment aims to find the differences in the microRNA profile of bone-marrow derived macrophages infected with Leishmania RNA virus containing L.guyanensis or virus-free parasites.
Project description:We evaluated the trancriptome of primary cutaneous leisions caused by infection with Leishmania braziliensis. mRNA-seq technique was used to study the trancriptome of both host and parasite. A total of 10 samples was obtained from primary skin ulcers of two extreme clinical forms of American tegumentary leishmaniasis: (i) individuals that after antimonial treatment cured completely (localized cutaneous leishmaniasis - LCL, n=5) and (ii) individuals that developed mucosal lesions in naso and oropharynx areas long after initial healing of the cutaneous lesion (mucosal leishmaniasis - ML, n=5). The sequencing generated an average of 13+ 5 million reads per samples. The reads were aligned to Homo sapiens (USCS - hg19) and to Leishmania braziliensis (Wellcome Trust Sanger Institute - V2_29072008) genomes. Approximately, 15,000 human genes could be detected in the samples. Low amount of L. braziliensis reads did not allow the evaluation of parasite gene expression. LCL and ML samples showed different patterns of gene expression, indicating a more robust immune response in LCL individuals. In summary, this study demonstrated that next-generation sequencing can be used for identification of potentially important biological pathways and drug targets in the host-response to L. braziliensis infection and for characterization of a gene expression signature that could be used to predict the disease outcome. Moreover, we also showed the ability of this technique in, simultaneously, sequence host and pathogen mRNA. Examination of 10 fragments of cutaneous lesions: 5 from localized cutaneous leishmaniasis patients and 5 from mucosal leishmaniasis patients.
Project description:Leishmania RNA virus 1 (LRV1) is a double stranded RNA (dsRNA) virus found in some strains of the human protozoan parasite Leishmania, the causative agent of leishmaniasis, a neglected tropical disease. Interestingly, the presence of LRV1 inside Leishmania constitutes an important virulence factor which worsens leishmaniasis outcome in a type I interferon (type I IFN) dependent manner and contributes to treatment failure. Understanding how macrophages respond towards Leishmania alone or in combination with LRV1 as well as the role that type I IFNs may play during infection is fundamental to oversee new therapeutic strategies. In order to dissect the macrophage response towards infection, RNA Sequencing (RNA-Seq) was performed on murine wild-type (WT) bone marrow derived macrophages infected with Leishmania guyanensis (Lgy) devoid or not of LRV1 (LgyLRV1- and LgyLRV1+ respectively) or co-infected with LgyLRV1- and Lymphocytic choriomeningitis virus (LCMV) for 8 and 24 hours. Additionally, macrophages were treated with type I IFN (IFNα or IFNβ) after 6 hours of infection.
Project description:The aim of this study was to identify differences in the NK-cell response towards Leishmania mexicana lipophosphoglycan (LPG) between patients with localized (LCL) and diffuse (DCL) cutaneous leishmaniasis through gene expression profiling, in an attempt to pinpoint alterations in the signaling pathways responsible for the NK-cell dysfunction in patients with DCL. To determine the gene expression profiling in non stimulated and LPG-stimulated NK cells we include samples of controls, LCL and DCL patients. We performed microarrays (Human Gene 1.0 ST, Affymetrix) to identify differentially expressed transcripts between non stimulated and LPG-stimulated NK cells between controls, LCL and DCL samples.
Project description:Leishmania amazonensis is a protozoan that primarily infects macrophages and causes cutaneous leishmaniasis in humans. MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression at posttranscriptional levels. Previous work demonstrated changes in miRNA profile of host cells favoring parasite survivel. Thus, here we demonstrate that human macrophages upregulate several miRNAs on the initial time points of infection, including the hsa-miR-372, hsa-miR-373, and hsa-miR-520d, which present the same seed. Further functional analysis demonstrated that inhibition of the miR-372 impaired Leishmania survival in THP-1 macrophages and the effect was further enhanced with combinatorial inhibition of the miR-372/373/520d family, pointing to a cooperative mechanism. Our study demonstrated miRNA-dependent modulation of polyamines production, establishing permissive conditions for intracellular parasite survival.Our findings suggest that the miR-372/373/520d family may represent a potential target for the development of new therapeutic strategies against cutaneous leishmaniasis.