Periodic Reporting for period 1 - Trojan (Redefining Tsetse symbiont bacteria: A Trojan horse against Trypanosome transmission)
Reporting period: 2020-05-01 to 2022-04-30
African trypanosomiasis is a vector-borne parasitic disease caused by protozoan parasites belonging to the genus Trypanosoma. It is transmitted to humans and animals by tsetse fly bites, causing the sleeping sickness or Human African Trypanosomiasis (HAT) and Nagana or Animal African Trypanosomiasis (AAT). HAT occurs in 36 sub-Saharan African countries in which 70 million inhabitants are at risk, with a prevalence of 300-500 thousand cases. Currently, treatments are unsatisfactory because of the complexity of their administration, the need for hospitalization and their high toxicity. On the other hand, the emergence of multidrug-resistant strains along with the absence of effective vaccines urgently requires the design of new strategies to eradicate the disease.
Recently, the existence of a molecular dialogue between the fly, the symbiont Sodalis, and the trypanosome has been demonstrated. Some genes of Sodalis increase or reduce their transcription levels in flies that had been infected by the parasites, even if the parasite is not established in the fly's midgut. This opens the door to the identification of promoters of Sodalis that can be induced by Trypanosoma to design Sodalis strains expressing certain compounds that hinder the vector competence (VC) only when it is infected.
Based on the above, the main objective of this project was the 1) the design of a new expression system in Sodalis sp. induced by the parasite, so that it was only active in infected flies, reducing or eliminating its ability to transfer the parasite through different routes and 2) the identification and evaluation of new compounds able to kill the parasite.
Recently, the existence of a molecular dialogue between the fly, the symbiont Sodalis, and the trypanosome has been demonstrated. Some genes of Sodalis increase or reduce their transcription levels in flies that had been infected by the parasites, even if the parasite is not established in the fly's midgut. This opens the door to the identification of promoters of Sodalis that can be induced by Trypanosoma to design Sodalis strains expressing certain compounds that hinder the vector competence (VC) only when it is infected.
Based on the above, the main objective of this project was the 1) the design of a new expression system in Sodalis sp. induced by the parasite, so that it was only active in infected flies, reducing or eliminating its ability to transfer the parasite through different routes and 2) the identification and evaluation of new compounds able to kill the parasite.
The lines that I have been developing are not limited only to the characterization from the point of view of the biological activity of new treatments against Human African Trypanosomiasis, but also include genomics and proteomics aspects, their toxicological and pharmacological characterization.
1. Identification of a secretion system in Sodalis able to export effectors proteins.
I was working on the identification of native secretion systems able to be used for the heterologous production of effector molecules as well as in the identification of lab plasmids able to replicate in S. glossinidius with an inducible promoter to test the functionality.
2. Characterization of Trypanosome-induced Sodalis genes for the design of the Trypanosoma inducible system.
At the same time, I was working on the identification and functional characterization of Trypanosoma-Activated Sodalis Promoters (TAP). According to literature, Sodalis is the only endosymbiont of the fly that grows in the usual culture media in the lab, and that can be genetically modified by general techniques. These two characteristics and their omnipresence in different parts of the fly as well as in other vectors that transmit parasites, make this organism an ideal model in the fight against insect-transmitted parasites.
3. Cloning the secretion system under the control of the Trypanosoma inducible system to express effectors involved in the killing of the parasite inside the fly, or the reduction of the vector competence.
4. Paratransgenesis of the newly designed flies into tse-tse flyes.
5. Repurposing drugs to fight neglected tropical diseases and action mechanism elucidation
Considering the difficulty of the development of new drugs, the timeline and the cost, drug repurposing for the treatment of infections has emerged as an effective alternative since the risk of failure is lower and requires a shorter time frame for the drug development as well as less money.
6. Synthesis and characterization of new leads against Trypanosomatidae:
One of the most promising research lines has been related to the identification of new leads with activity against trypanosomatids exploring also different targets G-quadruplexes (G4).
1. Identification of a secretion system in Sodalis able to export effectors proteins.
I was working on the identification of native secretion systems able to be used for the heterologous production of effector molecules as well as in the identification of lab plasmids able to replicate in S. glossinidius with an inducible promoter to test the functionality.
2. Characterization of Trypanosome-induced Sodalis genes for the design of the Trypanosoma inducible system.
At the same time, I was working on the identification and functional characterization of Trypanosoma-Activated Sodalis Promoters (TAP). According to literature, Sodalis is the only endosymbiont of the fly that grows in the usual culture media in the lab, and that can be genetically modified by general techniques. These two characteristics and their omnipresence in different parts of the fly as well as in other vectors that transmit parasites, make this organism an ideal model in the fight against insect-transmitted parasites.
3. Cloning the secretion system under the control of the Trypanosoma inducible system to express effectors involved in the killing of the parasite inside the fly, or the reduction of the vector competence.
4. Paratransgenesis of the newly designed flies into tse-tse flyes.
5. Repurposing drugs to fight neglected tropical diseases and action mechanism elucidation
Considering the difficulty of the development of new drugs, the timeline and the cost, drug repurposing for the treatment of infections has emerged as an effective alternative since the risk of failure is lower and requires a shorter time frame for the drug development as well as less money.
6. Synthesis and characterization of new leads against Trypanosomatidae:
One of the most promising research lines has been related to the identification of new leads with activity against trypanosomatids exploring also different targets G-quadruplexes (G4).
This project represents a multi-disciplinary state-of-the-art research training project, as it builds on various recent exciting new findings and achievements. The excellent scientific levels of the Molgen group and the stimulating and international research environment in the department have allowed me to complement my capabilities in the areas of great expertise where the MolGen research group is a top team. Identification of new and promising compounds active against T. brucei, would lead to industrial collaborations, possible clinical applications and maybe patents.
WHO´s ultimate objective is the elimination of human and animal African trypanosomiasis as a public health problem and the implementation of sustained surveillance in all diseases-endemic countries. Although during the last years the number of infected people has been reduced considerably, the difficulty of reaching endemic areas, the application of the treatments, the absence of vaccines, and the diagnosis of making it are not controlled, especially in the wake of the COVID pandemic. COVID-19 outbreak stretched the capacity of the health systems in Africa, promoting inaccessibility to quality health services. Despite the implementation of the health insurance scheme in some African countries like Nigeria, Ghana and Kenya; a good number of the population affected by the Neglected tropical diseases (NTDs) and people at-risk still wallow in abject poverty due to disease co-morbidities and out-of-pocket expenditures. Although NTDs have desolating effects on human health and socioeconomic development, COVID-19 further intensified the undesirable effects associated with the diseases on the impoverished communities.
The fight against neglected tropical diseases is a major international challenge, one that is vital to the development of some of the most vulnerable populations. G-quadruplexes and bismuth-salts compounds offer excellent opportunities for the development of innovative treatments for trypanosomiasis that could perhaps be extended to other protozoan diseases such as malaria or leishmaniasis: the genomes of T.brucei contain multiple putative G-quadruplex (G4) forming sequences which have recently been proposed to mediate processes relevant for parasite survival. G4 could be considered a potential target for a novel approach towards the development of antiparasitic drugs; on the other hand, bismuth-based salts as repurposing drugs for the treatment of human African trypanosomiasis is a highly strategy efficient, time-saving, low-cost and minimum risk of failure. The utilization of these drugs, which having already been tested safe in humans (bismuth salts have been used in medicine for over three centuries, particularly in the treatment of dyspepsia. Commonly used agents include colloidal bismuth subcitrate, bismuth subsalicylate and the newer ranitidine bismuth citrate. These are safe drugs which exert local effects on the gastroduodenal mucosa), and could be redirected to combat particularly, rare, difficult-to-treat diseases and neglected diseases.
Developed countries, and specifically the European Union, have the moral and legal obligation to collaborate in the development of “Third World countries” through economic, political and sanitary policies. These kinds of studies are essential within this type of policy
WHO´s ultimate objective is the elimination of human and animal African trypanosomiasis as a public health problem and the implementation of sustained surveillance in all diseases-endemic countries. Although during the last years the number of infected people has been reduced considerably, the difficulty of reaching endemic areas, the application of the treatments, the absence of vaccines, and the diagnosis of making it are not controlled, especially in the wake of the COVID pandemic. COVID-19 outbreak stretched the capacity of the health systems in Africa, promoting inaccessibility to quality health services. Despite the implementation of the health insurance scheme in some African countries like Nigeria, Ghana and Kenya; a good number of the population affected by the Neglected tropical diseases (NTDs) and people at-risk still wallow in abject poverty due to disease co-morbidities and out-of-pocket expenditures. Although NTDs have desolating effects on human health and socioeconomic development, COVID-19 further intensified the undesirable effects associated with the diseases on the impoverished communities.
The fight against neglected tropical diseases is a major international challenge, one that is vital to the development of some of the most vulnerable populations. G-quadruplexes and bismuth-salts compounds offer excellent opportunities for the development of innovative treatments for trypanosomiasis that could perhaps be extended to other protozoan diseases such as malaria or leishmaniasis: the genomes of T.brucei contain multiple putative G-quadruplex (G4) forming sequences which have recently been proposed to mediate processes relevant for parasite survival. G4 could be considered a potential target for a novel approach towards the development of antiparasitic drugs; on the other hand, bismuth-based salts as repurposing drugs for the treatment of human African trypanosomiasis is a highly strategy efficient, time-saving, low-cost and minimum risk of failure. The utilization of these drugs, which having already been tested safe in humans (bismuth salts have been used in medicine for over three centuries, particularly in the treatment of dyspepsia. Commonly used agents include colloidal bismuth subcitrate, bismuth subsalicylate and the newer ranitidine bismuth citrate. These are safe drugs which exert local effects on the gastroduodenal mucosa), and could be redirected to combat particularly, rare, difficult-to-treat diseases and neglected diseases.
Developed countries, and specifically the European Union, have the moral and legal obligation to collaborate in the development of “Third World countries” through economic, political and sanitary policies. These kinds of studies are essential within this type of policy