Abstract
Leishmaniasis remains a major public health problem worldwide with a prevalence of 12 million, an incidence of 1 million persons, and 350 million people being at risk. Murine models have been largely used for studying the host-pathogen relationship and developing effective chemotherapies against Leishmania parasites. Thus, preclinical imaging is crucial for monitoring the disease outcome. The aim of this protocol is to quantify parasite burden using bioluminescence in vivo imaging. Here, we describe a high-throughput imaging workflow, together with data acquisition and analysis ideal to assess in vivo parasite load in mouse models.
Keywords: Parasite, Leishmania, Quantification, Bioluminescence, Luciferase, Bio-imaging
Background
Leishmania parasites are the causative agents of the neglected tropical disease known as leishmaniasis. The disease outcome varies depending on different factors including the infecting species, the immune response of the host, the presence of an endosymbiotic virus within Leishmania parasites (Ives et al., 2011), or the co-infection with viruses such human immunodeficiency virus (HIV) or lymphocytic choriomeningitis mammarenavirus (LCMV) which can be detrimental for disease exacerbation (van Griensven et al., 2014; Rossi et al., 2017). Therefore, the study of parasite persistence using murine models has emerged in the past years (Eren et al., 2016). The quantification of parasite burden in experimental models of Leishmania infection has been commonly quantified by either Real-Time Quantitative Reverse Transcription PCR (qRT-PCR) or by limiting dilution assays upon euthanasia of animals (Hartley et al., 2016). In this protocol, we report a non-invasive technique for the quantification of parasite burden during the disease progression using luciferase expressing parasites (Ives et al., 2011; Hartley et al., 2018). Moreover, this approach can also be applied for the in vivo detection of other chemiluminescent agents such as luminol that is used as a readout of myeloperoxidase (MPO) activity in acute and chronic inflammatory diseases, or for any other organism expressing luciferase.
Materials and Reagents
Equipment
Software
Procedure
Data analysis
Notes
Recipes
Acknowledgments
We thank Slavica Masina for critical reading of the manuscript and Tiia Snäkä for the help with the video preparation. This research was supported by FNS grant No. 310030_173180 and No. IZRJZ3_164176/1 to NF and by aIRR to NF. This protocol was adapted from the protocol described in Ives et al. (2011) and Hartley et al. (2018).
Competing interests
The authors declare no competing interests.
Ethics
All animal protocols in this publication were approved by the Swiss Federal Veterinary Office (SFVO), under the authorization number 2113. Animal handling and experimental procedures were undertaken with strict adherence to ethical guidelines set out by the SFVO and under inspection by the Department of Security and Environment of the State of Vaud, Switzerland.
References
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