Discovery of pyrazolopyrrolidinones as potent, broad-spectrum inhibitors of infection.

Introduction: Leishmaniasis is a parasitic disease that affects more than 1 million people worldwide annually, predominantly in resource-limited settings. The challenge in compound development is to exhibit potent activity against the intracellular stage of the parasite (the stage present in the mammalian host) without harming the infected host cells. We have identified a compound series (pyrazolopyrrolidinones) active against the intracellular parasites of and ; the causative agents of visceral and cutaneous leishmaniasis in the Old World, respectively.

Predictions of novel Schistosoma mansoni - human protein interactions consistent with experimental data.

Infection by the human blood fluke, Schistosoma mansoni involves a variety of cross-species protein- protein interactions. The pathogen expresses a diverse arsenal of proteins that facilitate the breach of physical and biochemical barriers present in skin evasion of the immune system, and digestion of human plasma proteins including albumin and hemoglobin, allowing schistosomes to reside in the host for years. However, only a small number of specific interactions between S.

Exploration of Benzothiazole Rhodacyanines as Allosteric Inhibitors of Protein-Protein Interactions with Heat Shock Protein 70 (Hsp70).

Cancer cells rely on the chaperone heat shock protein 70 (Hsp70) for survival and proliferation. Recently, benzothiazole rhodacyanines have been shown to bind an allosteric site on Hsp70, interrupting its binding to nucleotide-exchange factors (NEFs) and promoting cell death in breast cancer cell lines. However, proof-of-concept molecules, such as JG-98, have relatively modest potency (EC ≈ 0.

Frontline Science: Multiple cathepsins promote inflammasome-independent, particle-induced cell death during NLRP3-dependent IL-1β activation.

Sterile particles cause several chronic, inflammatory diseases, characterized by repeating cycles of particle phagocytosis and inflammatory cell death. Recent studies have proposed that these processes are driven by the NLRP3 inflammasome, a platform activated by phagocytosed particles, which controls both caspase-1-dependent cell death (pyroptosis) and mature IL-1β secretion. After phagocytosis, particles can disrupt lysosomes, and inhibitor studies have suggested that the resulting release of a lysosomal protease-cathepsin B-into the cytosol somehow activates NLRP3.

Synthesis and Evaluation of Oxyguanidine Analogues of the Cysteine Protease Inhibitor WRR-483 against Cruzain.

A series of oxyguanidine analogues of the cysteine protease inhibitor WRR-483 were synthesized and evaluated against cruzain, the major cysteine protease of the protozoan parasite Trypanosoma cruzi. Kinetic analyses of these analogues indicated that they have comparable potency to previously prepared vinyl sulfone cruzain inhibitors. Co-crystal structures of the oxyguanidine analogues WRR-666 (4) and WRR-669 (7) bound to cruzain demonstrated different binding interactions with the cysteine protease, depending on the aryl moiety of the P1' inhibitor subunit.

Multiple Cathepsins Promote Pro-IL-1β Synthesis and NLRP3-Mediated IL-1β Activation.

Sterile particles induce robust inflammatory responses that underlie the pathogenesis of diseases like silicosis, gout, and atherosclerosis. A key cytokine mediating this response is IL-1β. The generation of bioactive IL-1β by sterile particles is mediated by the NOD-like receptor containing a pyrin domain 3 (NLRP3) inflammasome, although exactly how this occurs is incompletely resolved.

Corifungin, a new drug lead against Naegleria, identified from a high-throughput screen.

Primary amebic meningoencephalitis (PAM) is a rapidly fatal infection caused by the free-living ameba Naegleria fowleri. The drug of choice in treating PAM is the antifungal antibiotic amphotericin B, but its use is associated with severe adverse effects. Moreover, few patients treated with amphotericin B have survived PAM.

Diverse inhibitor chemotypes targeting Trypanosoma cruzi CYP51.

Background: Chagas Disease, a WHO- and NIH-designated neglected tropical disease, is endemic in Latin America and an emerging infection in North America and Europe as a result of population moves. Although a major cause of morbidity and mortality due to heart failure, as well as inflicting a heavy economic burden in affected regions, Chagas Disease elicits scant notice from the pharmaceutical industry because of adverse economic incentives. The discovery and development of new routes to chemotherapy for Chagas Disease is a clear priority.

A high-throughput drug screen for Entamoeba histolytica identifies a new lead and target.

Entamoeba histolytica, a protozoan intestinal parasite, is the causative agent of human amebiasis. Amebiasis is the fourth leading cause of death and the third leading cause of morbidity due to protozoan infections worldwide(1), resulting in ~70,000 deaths annually. E.

WormAssay: a novel computer application for whole-plate motion-based screening of macroscopic parasites.

Lymphatic filariasis is caused by filarial nematode parasites, including Brugia malayi. Adult worms live in the lymphatic system and cause a strong immune reaction that leads to the obstruction of lymph vessels and swelling of the extremities. Chronic disease leads to the painful and disfiguring condition known as elephantiasis.

The Trypanosoma cruzi protease cruzain mediates immune evasion.

Trypanosoma cruzi is the causative agent of Chagas' disease. Novel chemotherapy with the drug K11777 targets the major cysteine protease cruzain and disrupts amastigote intracellular development. Nevertheless, the biological role of the protease in infection and pathogenesis remains unclear as cruzain gene knockout failed due to genetic redundancy.

Drug discovery for neglected tropical diseases at the Sandler Center.

The Sandler Center's approach to target-based drug discovery for neglected tropical diseases is to focus on parasite targets that are homologous to human targets being actively investigated in the pharmaceutical industry. In this way we attempt to use both the know-how and actual chemical matter from other drug-development efforts to jump start the discovery process for neglected tropical diseases. Our approach is akin to drug repurposing, except that we seek to repurpose leads rather than drugs.

Structural basis for inhibition of cathepsin B drug target from the human blood fluke, Schistosoma mansoni.

Schistosomiasis caused by a parasitic blood fluke of the genus Schistosoma afflicts over 200 million people worldwide. Schistosoma mansoni cathepsin B1 (SmCB1) is a gut-associated peptidase that digests host blood proteins as a source of nutrients. It is under investigation as a drug target.

A screen against Leishmania intracellular amastigotes: comparison to a promastigote screen and identification of a host cell-specific hit.

The ability to screen compounds in a high-throughput manner is essential in the process of small molecule drug discovery. Critical to the success of screening strategies is the proper design of the assay, often implying a compromise between ease/speed and a biologically relevant setting. Leishmaniasis is a major neglected disease with limited therapeutic options.

Schistosomiasis: from drug deployment to drug development.

Purpose Of Review: Schistosomiasis is a chronic and morbid disease that affects hundreds of millions of the poorest individuals in (sub)tropical regions, particularly sub-Saharan Africa. Just one drug, praziquantel (PZQ), is available. As discussed, efforts to expand mass drug administration programs may accelerate the emergence of resistance.

High-throughput analysis of an RNAi library identifies novel kinase targets in Trypanosoma brucei.

New drugs are needed to treat human African trypanosomiasis because the currently approved treatments are toxic or limited in efficacy. One strategy for developing new drugs involves discovering novel genes whose products can be targeted for modulation by small-molecule chemotherapeutic agents. The Trypanosoma brucei genome contains many genes with the potential to become such targets.

Cysteine peptidases of kinetoplastid parasites.

We review Clan CA Family C1 peptidases of kinetoplastid parasites (Trypanosoma and Leishmania) with respect to biochemical and genetic diversity, genomic organization and stage-specificity and control of expression. We discuss their contributions to parasite metabolism, virulence and pathogenesis and modulation of the host's immune response. Their applications as vaccine candidates and diagnostic markers as well as their chemical and genetic validation as drug targets are also summarized.

An image-based assay for high throughput screening of Giardia lamblia.

Giardia lamblia is a protozoan parasite that causes widespread gastrointestinal illness. Drugs to treat giardiasis are limited, but efforts to discover new anti-giardial compounds are constrained by the lack of a facile system for cell culture and inhibitor testing. We achieved robust and reproducible growth of G.

Reverse type I inhibitor of Mycobacterium tuberculosis CYP125A1.

Cytochrome P450 CYP125A1 of Mycobacterium tuberculosis, a potential therapeutic target for tuberculosis in humans, initiates degradation of the aliphatic chain of host cholesterol and is essential for establishing M. tuberculosis infection in a mouse model of disease. We explored the interactions of CYP125A1 with a reverse type I inhibitor by X-ray structure analysis and UV-vis spectroscopy.

RNA interference in Schistosoma mansoni schistosomula: selectivity, sensitivity and operation for larger-scale screening.

Background: The possible emergence of resistance to the only available drug for schistosomiasis spurs drug discovery that has been recently incentivized by the availability of improved transcriptome and genome sequence information. Transient RNAi has emerged as a straightforward and important technique to interrogate that information through decreased or loss of gene function and identify potential drug targets. To date, RNAi studies in schistosome stages infecting humans have focused on single (or up to 3) genes of interest.

The oligopeptidase B of Leishmania regulates parasite enolase and immune evasion.

Proteases are a ubiquitous group of enzymes that play key roles in the life cycle of parasites, in the host-parasite relationship, and in the pathogenesis of parasitic diseases. Furthermore, proteases are targets for the development of new anti-parasitic therapy. Protozoan parasites like Leishmania predominantly express Clan CA cysteine proteases for key life cycle functions.