UK:Brazil Joint Centre Partnership in Leishmaniasis (JCPiL). work plan 1 molecular pathology of leishmaniasis: towards host-directed therapy in leishmaniases

Abstract

Understanding the pathophysiology of the various clinical forms of leishmaniasis found in Brazil requires a deep phenotyping of patient responses that operate at the site of infection. Aiming the phenotyping, there is an ongoing molecular pathology project (with MRC funding) including data sharing through a digital pathology platform. In this project, new multiplex immunohistochemistry and RNA-FISH assays, Nanostring whole tissue transcriptomics and Nanostring Digital Spatial Profiling (DSP) were developed with identification of some new targets for therapy at the University of York, initially in cases of CL caused by L. donovani in Sri Lanka. Besides standard procedures and clinical forms to enable quantification and reliable comparison of parameters of lesions were developed. Building on these achievements, in this WP1, we aim to procceed the deep phenotyping in patients across the spectrum of leishmaniasis found in Brazil, comparing cutaneous and mucosal lesions of patients infected with L. braziliensis and L. guyanensis as well as in bone marrow aspirates of patients with VL infected with L. infantum. Cognisant of that host-directed therapies, in contrast to current parasite therapy, will play a role in the treatment of patients with leishmaniasis (alone or as adjunct to conventional chemotherapy) and the increasing evidence that at least for some forms of leishmaniasis we observe similarities in the immunological profile of that found in the tumor microenvironment, we will focus on defining regulatory pathways or checkpoints pathways (eg IGF-I, IDO-1, IL-10, CTLA-4, PD-L1 / PD -1). In addition, with the advent of new approaches using Nanostring Digital Spatial Profiling RNA phenotyping will provide the development of new tools to analyse the expression of genes in a spatially resolved form in biopsy samples, providing an unprecedent insight into the host-parasite interaction. We aim to reach relevant, spatially resolved data on the immune mechanisms that operate in the various forms of leishmaniasis and on the response of the parasite to these, and to identify the host pathways that may be the focus for the development of new therapies for use alone or as an adjunct to conventional chemotherapy. With the development of avatar mice using control and patient cells and with infection with Leishmania strains derived from patients, assayss aiming treatment are planned with the use of inhibitors or immunotherapeutics as antigomirs. (AU)