Urinary metabolomic profiling of a cohort of Colombian patients with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune and multisystem disease with a high public health impact. Lupus nephritis (LN), commonly known as renal involvement in SLE, is associated with a poorer prognosis and increased rates of morbidity and mortality in patients with SLE. Identifying new urinary biomarkers that can be used for LN prognosis or diagnosis is essential and is part of current active research. In this study, we applied an untargeted metabolomics approach involving liquid and gas chromatography coupled with mass spectrometry to urine samples collected from 17 individuals with SLE and no kidney damage, 23 individuals with LN, and 10 clinically healthy controls (HCs) to identify differential metabolic profiles for SLE and LN. The data analysis revealed a differentially abundant metabolite expression profile for each study group, and those metabolites may act as potential differential biomarkers of SLE and LN. The differential metabolic pathways found between the LN and SLE patients with no kidney involvement included primary bile acid biosynthesis, branched-chain amino acid synthesis and degradation, pantothenate and coenzyme A biosynthesis, lysine degradation, and tryptophan metabolism. Receiver operating characteristic curve analysis revealed that monopalmitin, glycolic acid, and glutamic acid allowed for the differentiation of individuals with SLE and no kidney involvement and individuals with LN considering high confidence levels. While the results offer promise, it is important to recognize the significant influence of medications and other external factors on metabolomics studies. This impact has the potential to obscure differences in metabolic profiles, presenting a considerable challenge in the identification of disease biomarkers. Therefore, experimental validation should be conducted with a larger sample size to explore the diagnostic potential of the metabolites found as well as to examine how treatment and disease activity influence the identified chemical compounds. This will be crucial for refining the accuracy and effectiveness of using urine metabolomics for diagnosing and monitoring lupus and lupus nephritis.

CREditing: a tool for gene tuning in Trypanosoma cruzi.

The genetic manipulation of Trypanosoma cruzi continues to be a challenge, mainly due to the lack of available and efficient molecular tools. The CRE-lox recombination system is a site-specific recombinase technology, widely used method of achieving conditional targeted deletions, inversions, insertions, gene activation, translocation, and other modifications in chromosomal or episomal DNA. In the present study, the CRE-lox system was adapted to expand the current genetic toolbox for this hard-to-manipulate parasite. For this, evaluations of whether direct protein delivery of CRE recombinase through electroporation could improve CRE-mediated recombination in T. cruzi were performed. CRE recombinase was fused to the C-terminus of T. cruzi histone H2B, which carries the nuclear localization signal and is expressed in the prokaryotic system. The fusion protein was affinity purified and directly introduced into epimastigotes and tissue culture-derived trypomastigotes. This enabled the control of gene expression as demonstrated by turning on a tandem dimer fluorescent protein reporter gene that had been previously transfected into parasites, achieving CRE-mediated recombination in up to 85% of parasites. This system was further tested for its ability to turn off gene expression, remove selectable markers integrated into the genome, and conditionally knock down the nitroreductase gene, which is involved in drug resistance. Additionally, CREditing also enabled the control of gene expression in tissue culture trypomastigotes, which are more difficult to transfect than epimastigotes. The considerable advances in genomic manipulation of T. cruzi shown in this study can be used by others to aid in the greater understanding of this parasite through gain- or loss-of-function approaches.

Targeting epimastigotes of Trypanosoma cruzi with a peptide isolated from a phage display random library.

Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite Trypanosoma cruzi, which is transmitted by insects of the family Reduviidae. Since conventional treatments with nitroheterocyclic drugs show serious adverse reactions and have questionable efficiency, different research groups have investigated polypeptide-based approaches to interfere with the parasite cell cycle in other Trypanosomatids. These strategies are supported by the fact that surface players are candidates to develop surface ligands that impair function since they may act as virulence factors. In this study, we used a phage display approach to identify peptides from one library-LX8CX8 (17 aa) (where X corresponds to any amino acid). After testing different biopanning conditions using live or fixed epimastigotes, 10 clones were sequenced that encoded the same peptide, named here as EPI18. The bacteriophage expressing EPI18 binds to epimastigotes from distinct strains of T. cruzi. To confirm these results, this peptide was synthetized, biotinylated, and assayed using flow cytometry and confocal microscopy analyses. These assays confirmed the specificity of the binding capacity of EPI18 toward epimastigote surfaces. Our findings suggest that EPI18 may have potential biotechnological applications that include peptide-based strategies to control parasite transmission.

Engineering a single-chain antibody against Trypanosoma cruzi metacyclic trypomastigotes to block cell invasion.

Trypanosoma cruzi is a flagellate protozoan pathogen that causes Chagas disease. Currently there is no preventive treatment and the efficiency of the two drugs available is limited to the acute phase. Therefore, there is an unmet need for innovative tools to block transmission in endemic areas. In this study, we engineered a novel recombinant molecule able to adhere to the T. cruzi surface, termed scFv-10D8, that consists of a single-chain variable fragment (scFv) derived from mAb-10D8 that targets gp35/50. The synthetic gene encoding scFv-10D8 was cloned and fused to a 6×His tag and expressed in a prokaryotic expression system. Total periplasmic or 6xHis tag affinity-purified fractions of scFv-10D8 retained the capacity to bind to gp35/50, as shown by Western blot analyses. Pre-incubation of metacyclic trypomastigotes with scFv-10D8 showed a remarkable reduction in cell invasion capacity. Our results suggest that scFv-10D8 can be used in a paratransgenic approach to target parasites in insect vectors, avoiding dissemination of infective forms. Such advances in the development of this functional molecule will surely prompt the improvement of alternative strategies to control Chagas disease by targeting mammalian host stages.