Dataset Information

Development of an in vitro media perfusion model of Leishmania major macrophage infection.

ABSTRACT:

Background

In vitro assays are widely used in studies on pathogen infectivity, immune responses, drug and vaccine discovery. However, most in vitro assays display significant differences to the in vivo situation and limited predictive properties. We applied medium perfusion methods to mimic interstitial fluid flow to establish a novel infection model of Leishmania parasites.

Methods

Leishmania major infection of mouse peritoneal macrophages was studied within the Quasi Vivo QV900 macro-perfusion system. Under a constant flow of culture media at a rate of 360?l/min, L. major infected macrophages were cultured either at the base of a perfusion chamber or raised on 9mm high inserts. Mathematical and computational modelling was conducted to estimate medium flow speed, shear stress and oxygen concentration. The effects of medium flow on infection rate, intracellular amastigote division, macrophage phagocytosis and macropinocytosis were measured.

Results

Mean fluid speeds at the macrophage cell surface were estimated to be 1.45 x 10-9 m/s and 1.23 x 10-7 m/s for cells at the base of the chamber and cells on an insert, respectively. L. major macrophage infection was significantly reduced under both media perfusion conditions compared to cells maintained under static conditions; a 85±3% infection rate of macrophages at 72 hours in static cultures compared to 62±5% for cultures under slow medium flow and 55±3% under fast medium flow. Media perfusion also decreased amastigote replication and both macrophage phagocytosis (by 44±4% under slow flow and 57±5% under fast flow compared with the static condition) and macropinocytosis (by 40±4% under slow flow and 62±5% under fast flow compared with the static condition) as measured by uptake of latex beads and pHrodo Red dextran.

Conclusions

Perfusion of culture medium in an in vitro L. major macrophage infection model (simulating in vivo lymphatic flow) reduced the infection rate of macrophages, the replication of the intracellular parasite, macrophage phagocytosis and macropinocytosis with greater reductions achieved under faster flow speeds.

SUBMITTER: O'Keeffe A

PROVIDER: S-EPMC6656416 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Publications

Development of an in vitro media perfusion model of Leishmania major macrophage infection.

O'Keeffe Alec A Hyndman Lauren L McGinty Sean S Riezk Alaa A Murdan Sudaxshina S Croft Simon L SL

PloS one 20190724 7

<h4>Background</h4>In vitro assays are widely used in studies on pathogen infectivity, immune responses, drug and vaccine discovery. However, most in vitro assays display significant differences to the in vivo situation and limited predictive properties. We applied medium perfusion methods to mimic interstitial fluid flow to establish a novel infection model of Leishmania parasites.<h4>Methods</h4>Leishmania major infection of mouse peritoneal macrophages was studied within the Quasi Vivo QV900 ...[more]

PMID: 31339931

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Project description:Leishmania (L.) are obligated intracellular protozoan parasites that develop electively in macrophages. These cells that are acting as a safe shelter for the pathogens but also as their ultimate killer, making them the alpha and the omega during leishmaniasis diseases. Macrophages are able to secrete a remarkably diverse set of regulators known to influence the physiological functions and differentiation of neighboring cells to trigger an adaptive immune response of protective Th1-type cells, whereas parasites have developed a wide range of mechanisms to circumvent the hostâs immune responses. Most of our understanding of this host-parasite conflict, in the context of macrophage invasion by L. major metacyclic promastigotes, has been gleaned from studies investigating the macrophage responses at late and unique time points after infection. To investigate the dynamics of this duel, we have analyzed the transciptomic profile of monocyte-derived human macrophages at different time points during the first 24h upon in vitro infection using high throughput microarray platform. The gene expression profile of 17,838 genes showed high expression variability between the three human donors at different time points post infection. Cross comparison between the three donors allowed the identification of a common set of expressed genes coding for inflammatory and chemotactic molecules, transcription factors, apoptosis inhibition, glucose synthesis and heme metabolism. The findings presented in this work suggest that transcriptome dynamics of macrophages early during the first 24h post infection enable to identify novel key pathways deregulated upon L. major invasion. Our reported set of expressed genes will be useful in future rounds of data mining and functional analyses. In total 27 samples from three different donors were analyzed. For each donor, samples at 0h, 3h, 6h, 12h and 24h of culture were used as controls. For each donor, samples of cells infected with metacyclic Leishmania major parasites at 3h, 6h, 12h and 24h post-infection were analyzed.

Project description:BackgroundIn the Mediterranean basin, three Leishmania species have been identified: L. infantum, L. major and L. tropica, causing zoonotic visceral leishmaniasis (VL), zoonotic cutaneous leishmaniasis (CL) and anthroponotic CL, respectively. Despite animal models and genomic/transcriptomic studies provided important insights, the pathogenic determinants modulating the development of VL and CL are still poorly understood. This work aimed to identify host transcriptional signatures shared by cells infected with L. infantum, L. major, and L. tropica, as well as specific transcriptional signatures elicited by parasites causing VL (i.e., L. infantum) and parasites involved in CL (i.e., L. major, L. tropica).Methodology/principal findingsU937 cells differentiated into macrophage-like cells were infected with L. infantum, L. major and L. tropica for 24h and 48h, and total RNA was extracted. RNA sequencing, performed on an Illumina NovaSeq 6000 platform, was used to evaluate the transcriptional signatures of infected cells with respect to non-infected cells at both time points. The EdgeR package was used to identify differentially expressed genes (fold change > 2 and FDR-adjusted p-values < 0.05). Then, functional enrichment analysis was employed to identify the enriched ontology terms in which these genes are involved. At 24h post-infection, a common signature of 463 dysregulated genes shared among all infection conditions was recognized, while at 48h post-infection the common signature was reduced to 120 genes. Aside from a common transcriptional response, we evidenced different upregulated functional pathways characterizing L. infantum-infected cells, such as VEGFA-VEGFR2 and NFE2L2-related pathways, indicating vascular remodeling and reduction of oxidative stress as potentially important factors for visceralization.ConclusionsThe identification of pathways elicited by parasites causing VL or CL could lead to new therapeutic strategies for leishmaniasis, combining the canonical anti-leishmania compounds with host-directed therapy.

Dataset Information

Development of an in vitro media perfusion model of Leishmania major macrophage infection.

Background

Methods

Results

Conclusions

Publications

Development of an in vitro media perfusion model of Leishmania major macrophage infection.

Similar Datasets

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