Abstract - Journal of Clinical Immunology Research (2020) Volume 3, Issue 1

World Vaccine Meet 2019”: Modulation of the Expression of innate Immunity Markers by Human Macrophage THP1 Cells Following Infection with Leishmaniadonovani Isolates- Amal F.Al Dawi- Madinat Zayed-AbuDhabi -UAE

Protozoa of the genus Leishmania cause a wide variety of pathologies ranging from self-healing skin lesions to visceral pathology. The outcome of infection depends on the species of the infecting Leishmania parasite. A significant role of the adaptive immune response was described for the development of clinical disease and cure. While TH2 was associated with development of clinical disease,TH1 response was associated with cure.This study aimed to determine the profile of innate immunemarkers using Leishmania infected human THP1 macrophage cell lines. The parasite isolates were collected from patients suffering from cutaneous, Visceral, Post kala-Azar Dermal and mucosal leishmaniasis. Leishmania has developed an intricate relationship with its host, primarily cells of the monocyte/macrophage lineage, where it exploits and subverts the host immune system by either inducing immunosuppression or promoting proparasitic host factors to assure its endurance and growth in an otherwise harsh milieu. Leishmaniasis is induced by the protozoan parasite Leishmania. Depending on the species of the pathogen and the host's immune respose, the disease presents a spectrum from self-healing. cutaneoulesions to severe visceral disease and death. Leishmania is a digenetic organism, alternating between a flagellated promastigote in the gutof the phlebotomine sand fly and an intracellular amastigote residing within macrophages of the mammalian host, which ranges from desert rodents to humans. Infection with Leishmania initiates complex cascades of events in macrophages that influence the ensuing immune response. Several intracellular pathogens catch the phagosome maturation in the host cells to avoid transport to lysosomes. In diverge, the Leishmania containing parasitophorous vacuole (PV) is shown to volunteer lysosomal markers and thus Leishmania is hypothesize to be exist in the phagolysosomes in macrophages. Human macrophages affected with L. major showed a significant change in the expression pattern of a large number of miRNAs, suggesting their potential role in modulating the gene expression profile of the infected cells. Several miRNAs that were inflected in human macrophages after affected with L. major or L. donovani have been reported to be induced during inflammation and activation of toll-like receptors mediated by either pathogenic challenge or by bacterial lipopolysaccharides. Host cells are also known to initiate autophagy as a central innate defense mechanism. Autophagy is an progressively conserved cellular adaptive response against intra- or extracellular stress and signals such as starvation-induced nutrient deprivation, ER-stress and pathogenic abuse. Autophagy restricts bacterial and viral pathogens such as Group A Streptococcus, Salmonella, mycobacteria, Listeria, Rickettsia and viruses including herpes simplex virus and human cytomegalovirus. Children under the age of 1 year and adults above 50 years of age are highly susceptible to VL. The susceptible host genetic background, nutritional status especially malnutrition and immune suppression ameliorates the clinical outcome of the disease. Temporary transfection with a MIR30A-3p inhibitor followed by L. donovani infection developed the autophagic response and dwindled the intracellular parasite burden in both THP-1 cells and human monocyte-derived macrophages (HsMDM). BECN1/Beclin 1, the mammalian orthology of yeast Vps30/Atg6, is an essential autophagy-promoting protein that plays a vital role in the governance of cell death and survival. We account BECN1-dependent modulation of host cell autophagy in response to L. donovani infection. Pretreatment of L. donovani-infected macrophages with the MIR30A-3p mimic reduced and with antagomir increased the expression of BECN1 protein. We demonstrate that BECN1 is a powerful target of MIR30A-3p and this miRNA negatively improves BECN1 expression. While the host innate immune response against leishmaniasis is important, it is now clear that the T-cell mediated immunity and the cytokines produced from various immune cells play a crucial role in determining the disease outcome. However, the cytokines function in autocrine (locally) and paracrine (at a distance from the site of synthesis) fashion to regulate the immune response. A longitudinal study on Leishmania pathogenesis and disease recovery highlighted the role of helper T (Th)-cell response. Therefore, immune cells and their cytokines have been recognized as potential targets for immunotherapy to modulate the activity of factors that are crucial in the immune system for healing. In this context, the phenomenon called ?Th1-Th2 dichotomy? became popular based on the role of the cytokines produced by these cells in disease progression and/or host protection. Mosmann et al. reported for the first time that the cloned murine Th-cells are in two functional subsets namely Th1 and Th2 based on the production of IFN-? and IL-4, respectively . Thereafter, several studies demonstrated the key role of major cytokines [e.g., IL-10, Transforming growth factor (TGF)-?, IL-4, IL-6, IL-12, and IFN-?] that implicated the role of Th1/Th2 balance in disease progression or host protection. In general, Th1 type response mediates host resistance and Th2 type response associates with disease progression Human THP1 cells were infected by live promastioteof leishmaniadonovani isolates from cutaneous (CL), visceral (VL), Post Kala-Azar dermal Leishmaniasis (PKDL) and mucosal Leishmaniasis(ML) Patients. The expression of Toll like receptor TL22, TL4 and TL9 and expression of IFN-? and IL-10 cytokine was measured using Real Time PCR.The production of IL-1ß, IL-6 and TNF-? cytokines was measured using captured ELISA. A significant increase in the expression of TLR 2, TLR4 and TLR9 by L. donovani infected THP-1 from ML patients was detected. A higher concentration IL-6 and IL-1?was detected in supernatants of L.donovani infected human macrophage cell linesfrom CL patientscompared with VLand ML patients. Whereas IL-1? concentration was higher in L.donovaniinfected human macrophage cell lines from ML patients. Unlike in cutaneous leishmaniasis (CL), T-cells with Th2 phenotype are difficult to determine similarly, the association between Th1 response and disease protection to VL is complex in humans. Occasionally, individuals respond to the exposure of Leishmania antigens via T-cells even they have no prior exposure to the parasite; this is possible due to the cross-activity by other microorganisms. Results: Our data measured a significant increase in the expression of TLR 2 and TNF-? by THP-1 cell line infected with L.donovani isolate from mucosal patient. Leishmania isolates from mucosal and PKDL patients induced signifant gene expression of TLR 4 and TLR9. These results could contribute to better understanding of the dynamics of gene expression and production of co-inflammatory cytokines in host cells during leishmaniasis. Therefore, there is a urgency for in-depth analysis of the role of cytokines and Leishmania pathogenesis to get a comprehensive view of the complex interplay of Leishmania parasite and their hosts. This review aims to summarize and critically analyze the state-of-the-art knowledge relating to cytokines and VL pathogenesis. Special emphasis has been made for the identification of potential cytokine targets that could be used for the development of novel diagnostic assays and immunotherapies for the detection and treatment of VL. Author(s): Amal F.Al Dawi- Madinat Zayed

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