Repositioning drug strategy against Trypanosoma cruzi: lessons learned from HIV aspartyl peptidase inhibitors

Chagas disease (CD) is an old neglected problem that affects more than 6 million people through 21 endemic countries in Latin America. Despite being responsible for more than 12 thousand deaths per year, the disease disposes basically of two drugs for its treatment, the nitroimidazole benznidazole and the nitrofuran nifurtimox. However, these drugs have innumerous limitations that greatly reduce the chances of cure. In Brazil, for example, only benznidazole is available to treat CD patients. Therefore, some proof-of-concept phase II clinical trials focused on improving the current treatment with benznidazole, also comparing it with repositioned drugs or combining them. Indeed, repositioning already marketed drugs in view of combating neglected tropical diseases is a very interesting approach in the context of decreased time for approval, better treatment options and low cost for development and implementation. After the introduction of human immunodeficiency virus aspartyl peptidase inhibitors (HIV-PIs) in the treatment of acquired immune deficiency syndrome (AIDS), the prevalence and incidence of parasitic, fungal and bacterial co-infections suffered a marked reduction, making these HIV-PIs attractive for drug repositioning. In this line, the present perspective presents the promising and beneficial data concerning the effects of HIV-PIs on the clinically relevant forms of Trypanosoma cruzi (i.e., trypomastigotes and amastigotes) and also highlights the ultrastructural and physiological targets for the HIV-PIs on this parasite. Therefore, we raise the possibility that HIV-PIs could be considered as alternative treatment options in the struggle against CD.

Inhibitory effect of dipeptide peptidase inhibitors analogues on LPS-induced inflammatory response on microglia / 局解手术学杂志

Objective To study the inhibitory effect and mechanism of dipeptide peptidase inhibitors analogues on LPS -induced inflam-matory response on microglia .Methods Microglia cells were cultured ,isolated and purified from the neonatal Sprague-Dawley rats.Divided them into blank group ,negative control ,LPS group and medicine group ( parallel determination for 3 times each group ) after pharmacological preconditioning for 48 hours.The optimal concentration of microglia proliferation induced by LPS were measured by MTT assay .Observed the role of dipeptide peptidase inhibitors analogues on LPS-induced microglia in different concentrations .The interleukin1β( IL-1β) ,tumor necro-sis factor alpha ( TNF-α) were assayed by enzyme-linked immunorrbent assay ( ELISA ) .The expression of TLR-4 was detected by Western blotting and the expression of NF-κB was detected by RT-PCR.Results LPS induced the proliferation of microglia and significantly in-creased the release of inflammatory cytokines in LPS-stimulated primary microglia .Compared with the blank group ,dipeptide peptidase inhibi-tors analogues could inhibit this effect and the IC 50 values was 1.014 ×10 -2 mol/L to MG after pretreatment for 48 hours.Dipeptide peptidase inhibitors analogues could inhibit the release of TNF-αand IL-1 significantly(P<0.01),and it decreased the expression of TLR4 and NF-κB signif-icantly(P<0.01).Conclusion This research suggests that dipeptide peptidase inhibitors analogues restrain cell proliferation and inflammatory re-sponse of LPS-stimulated microglia,and the possible mechanism may be related to the inhibition of the expression of TLR-4 and NF-κB.

Introduction for clinical trials of aogliptin / 中国生化药物杂志

Alogliptin is a class of highly selective dipeptidyl peptidase-IV (DPP-IV) inhibitors.It can reduce the glucose level mainly through inhibiting the decomposition of dipeptidyl peptidase of glucagon peptide-1 (GLP-1), therefor promote insulin secretion.A large number of clinical trials have been conducted before and after algliptin get approved by Food and Drug Administration form different countries , which proves that alogliptin can remarkably reduce blood glucose without causing any serious risks.This article is mean to introduce most of the important clinical trials that has been conducted, from Phase I to Phase IV.

Una peptidasa ácida, insensible a inhibidores clásicos, en extractos proteicos de Trypanosoma cruzi, proveniente de una zona rural de Venezuela, endémica para la enfermedad de Chagas / Description of an acidic peptidase, insensitive to classical inhibitors, in protein extracts of Trypanosoma cruzi, from a rural area of Venezuela, where Chagas disease is endemic

Mediante dos métodos de ensayo de peptidasas, uno en fase líquida y otro en fase gel (zimografía en geles), se detectó una peptidasa, en extractos proteicos crudos de epimastigotes de Trypanosoma cruzi, provenientes de un área rural de Venezuela endémica para el mal de Chagas. La peptidasa mostró actividad en el intervalo de pH comprendido entre 2,0 y 2,9. Bajo las condiciones experimentales descritas, la peptidasa resultó insensible a concentraciones usuales de inhibidores clásicos de peptidasas de tipo: serina, cisteína, metalo-peptidasas y aspártico. No obstante, a semejanza de la pepsina porcina a pH 2,9, la peptidasa es inhibida en presencia de 5mM DTT.

Through two peptidase assay methods, one in liquid-phase and another, in gel-phase (gel zymography), an acid peptidase was detected in protein crude extracts of epimastigotes of Trypanosoma cruzi, from a rural area of Venezuela where Chagas disease is endemic. The peptidase shows activity at a pH range between 2.0 and 2.9. Under the experimental conditions described, the acid peptidase was insensitive to usual concentrations of peptidase inhibitors of the types: serine, cysteine, aspartic and metallo-peptidases. Nevertheless, like porcine pepsin at pH 2.9, the peptidase was inhibited in the presence of 5mM DTT.