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34 Publications visible to you, out of a total of 34

Abstract (Expand)

The application of in vivo bioluminescent imaging in infectious disease research has significantly increased over the past years. The detection of transgenic parasites expressing wildtype firefly luciferase is however hampered by a relatively low and heterogeneous tissue penetrating capacity of emitted light. Solutions are sought by using codon-optimized red-shifted luciferases that yield higher expression levels and produce relatively more red or near-infrared light, or by using modified bioluminescent substrates with enhanced cell permeability and improved luminogenic or pharmacokinetic properties. In this study, the in vitro and in vivo efficacy of two modified bioluminescent substrates, CycLuc1 and AkaLumine-HCl, were compared with that of D-luciferin as a gold standard. Comparisons were made in experimental and insect-transmitted animal models of leishmaniasis (caused by intracellular Leishmania species) and African trypanosomiasis (caused by extracellular Trypanosoma species), using parasite strains expressing the red-shifted firefly luciferase PpyRE9. Although the luminogenic properties of AkaLumine-HCl and D-luciferin for in vitro parasite detection were comparable at equal substrate concentrations, AkaLumine-HCl proved to be unsuitable for in vivo infection follow-up due to high background signals in the liver. CycLuc1 presented a higher in vitro luminescence compared to the other substrates and proved to be highly efficacious in vivo, even at a 20-fold lower dose than D-luciferin. This efficacy was consistent across infections with the herein included intracellular and extracellular parasitic organisms. It can be concluded that CycLuc1 is an excellent and broadly applicable alternative for D-luciferin, requiring significantly lower doses for in vivo bioluminescent imaging in rodent models of leishmaniasis and African trypanosomiasis.

Authors: Sarah Hendrickx, Dimitri Bulté, Dorien Mabille, Roxanne Mols, Mathieu Claes, Kayhan Ilbeigi, Rokaya Ahmad, Laura Dirkx, Sara I. Van Acker, Guy Caljon

Date Published: 16th Dec 2022

Publication Type: Journal Article

Abstract (Expand)

The application of in vivo bioluminescent imaging in infectious disease research has significantly increased over the past years. The detection of transgenic parasites expressing wildtype firefly luciferase is however hampered by a relatively low and heterogeneous tissue penetrating capacity of emitted light. Solutions are sought by using codon-optimized red-shifted luciferases that yield higher expression levels and produce relatively more red or near-infrared light, or by using modified bioluminescent substrates with enhanced cell permeability and improved luminogenic or pharmacokinetic properties. In this study, the in vitro and in vivo efficacy of two modified bioluminescent substrates, CycLuc1 and AkaLumine-HCl, were compared with that of D-luciferin as a gold standard. Comparisons were made in experimental and insect-transmitted animal models of leishmaniasis (caused by intracellular Leishmania species) and African trypanosomiasis (caused by extracellular Trypanosoma species), using parasite strains expressing the red-shifted firefly luciferase PpyRE9. Although the luminogenic properties of AkaLumine-HCl and D-luciferin for in vitro parasite detection were comparable at equal substrate concentrations, AkaLumine-HCl proved to be unsuitable for in vivo infection follow-up due to high background signals in the liver. CycLuc1 presented a higher in vitro luminescence compared to the other substrates and proved to be highly efficacious in vivo, even at a 20-fold lower dose than D-luciferin. This efficacy was consistent across infections with the herein included intracellular and extracellular parasitic organisms. It can be concluded that CycLuc1 is an excellent and broadly applicable alternative for D-luciferin, requiring significantly lower doses for in vivo bioluminescent imaging in rodent models of leishmaniasis and African trypanosomiasis.

Authors: S. Hendrickx, D. Bulte, D. Mabille, R. Mols, M. Claes, K. Ilbeigi, R. Ahmad, L. Dirkx, S. I. Van Acker, G. Caljon

Date Published: 16th Dec 2022

Publication Type: Journal Article

Abstract (Expand)

AbstractApproximately 20% of sleeping sickness patients exhibit respiratory complications, however, with a largely unknown role of the parasite. Here we show that tsetse fly-transmitted Trypanosoma brucei parasites rapidly and permanently colonize the lungs and occupy the extravascular spaces surrounding the blood vessels of the alveoli and bronchi. They are present as nests of multiplying parasites exhibiting close interactions with collagen and active secretion of extracellular vesicles. The local immune response shows a substantial increase of monocytes, macrophages, dendritic cells and γδ and activated αβ T cells and a later influx of neutrophils. Interestingly, parasite presence results in a significant reduction of B cells, eosinophils and natural killer cells. T. brucei infected mice show no infection-associated pulmonary dysfunction, mirroring the limited pulmonary clinical complications during sleeping sickness. However, the substantial reduction of the various immune cells may render individuals more susceptible to opportunistic infections, as evident by a co-infection experiment with respiratory syncytial virus. Collectively, these observations provide insights into a largely overlooked target organ, and may trigger new diagnostic and supportive therapeutic approaches for sleeping sickness.

Authors: Dorien Mabille, Laura Dirkx, Sofie Thys, Marjorie Vermeersch, Daniel Montenye, Matthias Govaerts, Sarah Hendrickx, Peter Takac, Johan Van Weyenbergh, Isabel Pintelon, Peter Delputte, Louis Maes, David Pérez-Morga, Jean-Pierre Timmermans, Guy Caljon

Date Published: 18th Nov 2022

Publication Type: Journal Article

Abstract (Expand)

Approximately 20% of sleeping sickness patients exhibit respiratory complications, however, with a largely unknown role of the parasite. Here we show that tsetse fly-transmitted Trypanosoma brucei parasites rapidly and permanently colonize the lungs and occupy the extravascular spaces surrounding the blood vessels of the alveoli and bronchi. They are present as nests of multiplying parasites exhibiting close interactions with collagen and active secretion of extracellular vesicles. The local immune response shows a substantial increase of monocytes, macrophages, dendritic cells and gammadelta and activated alphabeta T cells and a later influx of neutrophils. Interestingly, parasite presence results in a significant reduction of B cells, eosinophils and natural killer cells. T. brucei infected mice show no infection-associated pulmonary dysfunction, mirroring the limited pulmonary clinical complications during sleeping sickness. However, the substantial reduction of the various immune cells may render individuals more susceptible to opportunistic infections, as evident by a co-infection experiment with respiratory syncytial virus. Collectively, these observations provide insights into a largely overlooked target organ, and may trigger new diagnostic and supportive therapeutic approaches for sleeping sickness.

Authors: D. Mabille, L. Dirkx, S. Thys, M. Vermeersch, D. Montenye, M. Govaerts, S. Hendrickx, P. Takac, J. Van Weyenbergh, I. Pintelon, P. Delputte, L. Maes, D. Perez-Morga, J. P. Timmermans, G. Caljon

Date Published: 18th Nov 2022

Publication Type: Journal Article

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