Novel lactate dehydrogenase inhibitors with in vivo efficacy against Cryptosporidium parvum.

Kun Li,Aditi Das,Sara M Nader,William H Witola,Chi Yong Kim,Xuejin Zhang,Benjamin C Ray,Laura J Knoll

doi:10.1371/journal.ppat.1007953

Kun Li, Aditi Das + Show 6 more

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https://doi.org/10.1371/journal.ppat.1007953

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Journal: PLoS Pathogens	Publication Date: Jul 29, 2019
Citations: 23	License type: CC BY 4.0

Affiliation: University of Illinois Urbana-Champaign

Abstract

Cryptosporidium parvum is a highly prevalent zoonotic and anthroponotic protozoan parasite that causes a diarrheal syndrome in children and neonatal livestock, culminating in growth retardation and mortalities. Despite the high prevalence of C. parvum, there are no fully effective and safe drugs for treating infections, and there is no vaccine. We have previously reported that the bacterial-like C. parvum lactate dehydrogenase (CpLDH) enzyme is essential for survival, virulence and growth of C. parvum in vitro and in vivo. In the present study, we screened compound libraries and identified inhibitors against the enzymatic activity of recombinant CpLDH protein in vitro. We tested the inhibitors for anti-Cryptosporidium effect using in vitro infection assays of HCT-8 cells monolayers and identified compounds NSC158011 and NSC10447 that inhibited the proliferation of intracellular C. parvum in vitro, with IC50 values of 14.88 and 72.65 μM, respectively. At doses tolerable in mice, we found that both NSC158011 and NSC10447 consistently significantly reduced the shedding of C. parvum oocysts in infected immunocompromised mice’s feces, and prevented intestinal villous atrophy as well as mucosal erosion due to C. parvum. Together, our findings have unveiled promising anti-Cryptosporidium drug candidates that can be explored further for the development of the much needed novel therapeutic agents against C. parvum infections.

Highlights

The zoonotic and anthroponotic protozoan parasite, Cryptosporidium parvum, is a major cause of diarrheal diseases in children under the age of two, resulting in significant morbidity and mortality in poor-resource areas of developing countries [1]
The cloned open reading frame of C. parvum lactate dehydrogenase (CpLDH) gene was verified to be 966 bp long, and 99.79% identical to that reported in the genome database
By analyzing the in vitro catalytic activities of recombinant CpLDH, we found that it depicted more activity in catalyzing the reduction of pyruvate to lactate than the oxidation of lactate to pyruvate

Summary

Introduction

The zoonotic and anthroponotic protozoan parasite, Cryptosporidium parvum, is a major cause of diarrheal diseases in children under the age of two, resulting in significant morbidity and mortality in poor-resource areas of developing countries [1]. In calves, lambs and goat kids, it causes a serious diarrheal syndrome, culminating in growth retardation and high neonatal mortalities [2,3,4]. C. parvum is highly prevalent because of its enormous capacity to reproduce in infected livestock, resulting in large amounts of infective parasite oocysts being shed in animal feces, and contaminating water sources as well as the general environment. Nitazoxanide is ineffective in those individuals most at risk for morbidity and mortality due to Cryptosporidium infections, including malnourished children and immunocompromised individuals [6].

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