Protozoan Parasitic Infections Research Articles

Molecular detection of intestinal parasites in a rural community of Colombia: A one health approach to explore potential environmental-zoonotic transmission.

Protozoan and helminth parasitic infections pose significant public health challenges, especially in developing countries with rural populations marked by suboptimal hygiene practices and socio-economic constraints. The parasites are the etiological agents of these infections and have a notably elevated global prevalence. Therefore, this study focuses on estimating the frequency and transmission dynamics of several parasitic species, including Blastocystis, Giardia, Cryptosporidium spp., Entamoeba histolytica, Ascaris lumbricoides, Trichuris trichiura, Taenia spp. and hookworms, within a rural community in southwest Colombia with a particular emphasis on the One Health framework, considering environmental and zoonotic transmission potentials. This study involved the analysis of 125 samples, encompassing human participants (n = 99), their domestic pets (dogs) (n = 24) and water sources (n = 2). Parasite detection was carried out utilizing a combination of microscopy and molecular techniques. Furthermore, the characterization of Blastocystis subtypes (STs) was achieved through Oxford Nanopore sequencing of the rRNA-18S gene. The investigation also entailed the examination of potential associations between intestinal parasitism and various sociodemographic factors. Results revealed a high frequency of parasitic infections when employing molecular methods, with Blastocystis (n = 109/87%), Giardia (n = 20/16%), Ancylostoma duodenale (n = 28/22%), Ancylostoma ceylanicum (n = 7/5.6%), E. histolytica (n = 6/4.8%), Cryptosporidium spp. (n = 12/9.6%) and even Taenia (n = 1/0.8%) detected. Cryptosporidium spp. was also identified in water samples. Coinfections were prevalent, with 57% (n = 70) of samples exhibiting single-parasite infections and 43% (n = 53) showing various degrees of polyparasitism, emphasizing the complexity of transmission dynamics. Blastocystis subtyping, conducted via Oxford Nanopore sequencing, revealed a diversity of subtypes and coexistence patterns, with ST2 being the most prevalent. This research underscores the importance of using molecular techniques for frequency estimation, particularly emphasizing the relevance of zoonotic transmission in parasitic infections. It highlights the significance of the One Health approach in comprehending the circulation of parasites among animals, humans and environmental sources, thereby directly impacting public health and epidemiological surveillance.

Neutrophils versus Protozoan Parasites: Plasmodium, Trichomonas, Leishmania, Trypanosoma, and Entameoba.

Neutrophils are the most abundant polymorphonuclear granular leukocytes in human blood and are an essential part of the innate immune system. Neutrophils are efficient cells that eliminate pathogenic bacteria and fungi, but their role in dealing with protozoan parasitic infections remains controversial. At sites of protozoan parasite infections, a large number of infiltrating neutrophils is observed, suggesting that neutrophils are important cells for controlling the infection. Yet, in most cases, there is also a strong inflammatory response that can provoke tissue damage. Diseases like malaria, trichomoniasis, leishmaniasis, Chagas disease, and amoebiasis affect millions of people globally. In this review, we summarize these protozoan diseases and describe the novel view on how neutrophils are involved in protection from these parasites. Also, we present recent evidence that neutrophils play a double role in these infections participating both in control of the parasite and in the pathogenesis of the disease.

Pathogen‐binding nanoparticles to inhibit host cell infection by heparan sulfate and sialic acid dependent viruses and protozoan parasites

AbstractGlobal health faces an immense burden from infectious diseases caused by viruses and intracellular protozoan parasites such as the coronavirus disease (COVID‐19) and malaria, respectively. These pathogens propagate through the infection of human host cells. The first stage of this host cell infection mechanism is cell attachment, which typically involves interactions between the infectious agent and surface components on the host cell membranes, specifically heparan sulfate (HS) and/or sialic acid (SA). Hence, nanoparticles (NPs) which contain or mimic HS/SA that can directly bind to the pathogen surface and inhibit cell infection are emerging as potential candidates for an alternative anti‐infection therapeutic strategy. These NPs can be prepared from metals, soft matter (lipid, polymer, and dendrimer), DNA, and carbon‐based materials among others and can be designed to include aspects of multivalency, broad‐spectrum activity, biocidal mechanisms, and multifunctionality. This review provides an overview of such anti‐pathogen nanomedicines beyond drug delivery. Nanoscale inhibitors acting against viruses and obligate intracellular protozoan parasites are discussed. In the future, the availability of broadly applicable nanotherapeutics would allow early tackling of existing and upcoming viral diseases. Invasion inhibitory NPs could also provide urgently needed effective treatments for protozoan parasitic infections.

Prevalence of Cryptosporidium and Giardia infections in under-five children with diarrhoea in Blantyre, Malawi

BackgroundDiarrhoeal diseases are common among children in low- and middle-income countries and are major causes of morbidity and mortality. Cryptosporidium and Giardia are considered to be the main parasitic causes of diarrhoea in children. The aim of the present study was to determine the prevalence and associated factors of Cryptosporidium and Giardia infection in children under five years of age presenting at two health centres (Ndirande and Limbe) in Blantyre, Malawi.MethodsThis cross-sectional study was performed from February to July 2019 and included 972 children under 5 years of age with diarrhoea. Stool samples were immediately tested after collection at enrolment with a rapid diagnostic test for Cryptosporidium and Giardia infection. Descriptive statistics were used to assess the prevalence of these protozoan parasitic infections, and differences in the basic demographic and anthroponotic variables (between children with diarrhoea and parasite infection, being either Cryptosporidium and Giardia or both versus children with diarrhoea but no RDT confirmed parasite infection) were assessed. Their association with Cryptosporidium and Giardia infection was analysed using simple logistic regressions.ResultsOf the children recruited, 88 (9.1%) tested positive for Cryptosporidium and 184 (18.9%) for Giardia. Children with only a Giardia infection or a coinfection (of both parasites) were significantly older (mean age 24–26 months) compared to children with only a Cryptosporidium infection (mean age 13 months) or no parasitic infection (mean age 14 months). No significant differences were found with respect to gender, body temperature, stunting or wasting between the different groups of children with moderate to severe diarrhoea. Children attending the Ndirande health centre had almost two times higher odds of testing positive for both infections than those attending Limbe health centre.ConclusionCryptosporidium and Giardia infections are highly prevalent in children < 5 years with moderate to severe diarrhoea attending the Limbe and Ndirande health centres in Blantyre, Malawi.

Intestinal Protozoans among HIV Patients in a Rural Setting, Southern Nigeria

Opportunistic parasitic protozoan infections in HIV infected patients remain a worldwide public health concern. A cross sectional study on HIV patients was carried out in some parts of Imo State with a view of assessing the prevalence of intestinal protozoan parasites. Stool samples were collected and analysed applying standard techniques. Overall, four species of protozoan parasites were isolated namely, C.parvum, E.histolytica, G.lamblia and Ent. coli. Total prevalence is highest (52.2%) amongst the age group of ≤27 years, followed by 45-48years(27.8%) while the least prevalence(11.8%) is recorded for the age group of 49 years and above. More female (26.3%) were infected than male (25.4%). Significant association between age and protozoan prevalencewas noted(p-value=0.007; X2=32.998a, df=16). Further analysis selecting Cramer’s V which is the measure of association based on chi-square shows a weak dependence between age and parasite prevalence (Cramer’s V-value = 0.286). Pearson correlation shows a positive, weak (R=0.170; sig.=0.089c) relationship between age and protozoan parasite prevalence. Test of association between gender and intestinal protozoan parasites shows a non-significant association(p=0.280;X2=5.069a), weak dependence(Cramer’s V-value = 0.280) and a negative, weak relationship between gender and parasite prevalence(R=-0.042; sig=0.674c). Subjects with CD4count &lt;200µ/ml recorded the highest(40.0%) prevalence of intestinal protozoan parasite while 200-349µ/ml recorded the least prevalence(4.0%).Significant association exists between CD4 count and parasite prevalence(x2=53.9a, df=12,p=0.001);then Cramer’s v test shows a medium-strong dependence. High prevalence (37.0%) of intestinal protozoan parasites is recorded for subjects not on HAART while low prevalence (12.8%) is recorded for those on HAART; with Significant association (x2=16.157a, df=4, p=0.003) and medium-strong dependence (Cramer’s v =0.40).The result of this study shows that intestinal parasites are of public health concern among immunocompromised individuals and calls for urgent attention of relevant stakeholders

A molecular signature for IL-10-producing Th1 cells in protozoan parasitic diseases.

Control of visceral leishmaniasis (VL) depends on proinflammatory Th1 cells that activate infected tissue macrophages to kill resident intracellular parasites. However, proinflammatory cytokines produced by Th1 cells can damage tissues and require tight regulation. Th1 cell IL-10 production is an important cell-autologous mechanism to prevent such damage. However, IL-10-producing Th1 (type 1 regulatory; Tr1) cells can also delay control of parasites and the generation of immunity following drug treatment or vaccination. To identify molecules to target in order to alter the balance between Th1 and Tr1 cells for improved antiparasitic immunity, we compared the molecular and phenotypic profiles of Th1 and Tr1 cells in experimental VL caused by Leishmania donovani infection of C57BL/6J mice. We also identified a shared Tr1 cell protozoan signature by comparing the transcriptional profiles of Tr1 cells from mice with experimental VL and malaria. We identified LAG3 as an important coinhibitory receptor in patients with VL and experimental VL, and we reveal tissue-specific heterogeneity of coinhibitory receptor expression by Tr1 cells. We also discovered a role for the transcription factor Pbx1 in suppressing CD4+ T cell cytokine production. This work provides insights into the development and function of CD4+ T cells during protozoan parasitic infections and identifies key immunoregulatory molecules.

The detection and phylogenetic characterization of Cryptosporidium, Cystoisospora, and Giardia duodenalis of cats in South Korea.

Cryptosporidium, Cystoisospora, and Giardia duodenalis are gastrointestinal protozoa parasites that cause diarrhea in various animals. However, information regarding the detection and phylogenetic characterization of gastrointestinal protozoa parasites in cats is limited throughout South Korea. Therefore, this study aimed to determine the detection and identify subspecies of gastrointestinal protozoa parasites in cats from South Korea. A total of 290 fecal samples were collected from stray, companion, and shelter cats in six provinces. Cryptosporidium, Cystoisospora, and G. duodenalis were identified by PCR. All positive samples were subtyped by PCR and sequencing of gp60, ITS-1, tpi, bg, and gdh. The overall detection of gastrointestinal protozoan parasitic infection was 17.93%. G. duodenalis was the most prevalent, with 7.93%, followed by Cystoisospora spp. (7.24%) and Cryptosporidium spp. (4.48%). In addition, C. felis (n=10), C. parvum (n=2), C. ryanae (n=1), Cystoisospora felis (n=14), Cystoisospora suis (n=5), Cystoisospora ohioensis (n=1), Cystoisospora spp. were identified in subspecies analysis of positive samples. C. felis showed a significant association with diarrhea (7.81%) and living condition (6.04%), and Cystoisospora felis in diarreha (9.38%) according to detection. Through phylogenetic analysis of the tpi, bg, and gdh genes from 23 G. duodenalispositive samples, it was confirmed that the samples of present study belonged to assemblage A, B, C, and D. South Korean cats have a high rate of gastrointestinal protozoan parasites infection with cat-specific Cryptosporidium and Cystoisospora, which are associated with living conditions and diarrhea symptoms. Moreover, zoonotic and other animal-specific subtype of protozoan parasites have been detected in cat feces.

Morphological and molecular phylogenetic analyses of the apicomplexan parasites, Eimeria media and Eimeria stiedai, infecting the domestic rabbits, Oryctolagus cuniculus

The eimerian infection is one of the most serious infections that can decrease rabbit productivity since it can lead to serious diseases. There is little information about Eimeria media and Eimeria stiedai infections in Saudi Arabia, and molecular data is particularly weak. To establish the prevalence, morphological and molecular characterization of E. media and E. stiedai isolated from spontaneously infected rabbits, the current study was conducted. Ten healthy rabbits, Oryctolagus cuniculus, whose feces were collected and kept at the laboratory were examined for protozoan parasite infection using the floatation method. Purified oocysts were used to extract DNA, which was then used in a polymerase chain reaction (PCR) with primers that amplified a partial sequences of the 18S rDNA gene. Seven rabbits had coinfections with two eimerian species. Sporulated oocysts of E. media had an obvious micropyle and were oval, measuring 24.92–30.03 (28.04) µm in length and 16.33–19.63 (18.31) µm in width. In contrast, E. stiedai were ellipsoid and measured 31.03–36.47 (33.79) µm in length and 18.21–20.93 (19.32) µm in width. The identity of the species of Eimeria parasites detected from the host (rabbits) was verified by the results of the sequences for the 18S rDNA gene. Both organisms (E. media and E. stiedai) grouped with rabbit eimerian parasites with distinct association with the group that contains oocysts residual body. Sequences from E. stiedai revealed insertions on two sites that had never been detected in E. stiedai sequences previously deposited in GenBank. The current parasite species are closely related to the previously described and deposited E. media and E. stiedai and are deeply embedded in the genus Eimeria (family Eimeriidae). This study emphasized the significance of combining taxonomy with morphological and genetic data in the identification of Eimeria species.

Novel computational and drug design strategies for inhibition of monkeypox virus and Babesia microti: molecular docking, molecular dynamic simulation and drug design approach by natural compounds.

The alarming increase in tick-borne pathogens such as human Babesia microti is an existential threat to global public health. It is a protozoan parasitic infection transmitted by numerous species of the genus Babesia. Second, monkeypox has recently emerged as a public health crisis, and the virus has spread around the world in the post-COVID-19 period with a very rapid transmission rate. These two novel pathogens are a new concern for human health globally and have become a significant obstacle to the development of modern medicine and the economy of the whole world. Currently, there are no approved drugs for the treatment of this disease. So, this research gap encourages us to find a potential inhibitor from a natural source. In this study, a series of natural plant-based biomolecules were subjected to in-depth computational investigation to find the most potent inhibitors targeting major pathogenic proteins responsible for the diseases caused by these two pathogens. Among them, most of the selected natural compounds are predicted to bind tightly to the targeted proteins that are crucial for the replication of these novel pathogens. Moreover, all the molecules have outstanding ADMET properties such as high aqueous solubility, a higher human gastrointestinal absorption rate, and a lack of any carcinogenic or hepatotoxic effects; most of them followed Lipinski's rule. Finally, the stability of the compounds was determined by molecular dynamics simulations (MDs) for 100 ns. During MDs, we observed that the mentioned compounds have exceptional stability against selected pathogens. These advanced computational strategies reported that 11 lead compounds, including dieckol and amentoflavone, exhibited high potency, excellent drug-like properties, and no toxicity. These compounds demonstrated strong binding affinities to the target enzymes, especially dieckol, which displayed superior stability during molecular dynamics simulations. The MM/PBSA method confirmed the favorable binding energies of amentoflavone and dieckol. However, further in vitro and in vivo studies are necessary to validate their efficacy. Our research highlights the role of Dieckol and Amentoflavone as promising candidates for inhibiting both monkeypox and Babesia microti, demonstrating their multifaceted roles in the control of these pathogens.

P07-016-23 Symptomatic and Asymptomatic Enteric Protozoan Parasitic Infection and Their Association With Growth in Young Under 5 Children in South Asia and Sub-Saharan Africa

P07-016-23 Symptomatic and Asymptomatic Enteric Protozoan Parasitic Infection and Their Association With Growth in Young Under 5 Children in South Asia and Sub-Saharan Africa

Unfolded protein response is involved in resistance to Neospora caninum infection via IRE1α-XBP1s-NOD2 Axis.

Neospora caninum, an intracellular protozoan parasite, causes neosporosis resulting in major losses in the livestock industry worldwide. However, no effective drugs or vaccines have been developed to control neosporosis. An in-depth study on the immune response against N. caninum could help to search for effective approaches to prevent and treat neosporosis. The host unfolded protein response (UPR) functions as a double-edged sword in several protozoan parasite infections, either to initiate immune responses or to help parasite survival. In this study, the roles of the UPR in N. caninum infection in vitro and in vivo were explored, and the mechanism of the UPR in resistance to N. caninum infection was analyzed. The results revealed that N. caninum triggered the UPR in mouse macrophages, such as the activation of the IRE1 and PERK branches, but not the ATF6 branch. Inhibition of the IRE1α-XBP1s branch increased the N. caninum number both in vitro and in vivo, while inhibition of the PERK branch did not affect the parasite number. Furthermore, inhibition of the IRE1α-XBP1s branch reduced the production of cytokines by inhibiting NOD2 signalling and its downstream NF-κB and MAPK pathways. Taken together, the results of this study suggest that the UPR is involved in the resistance of N. caninum infection via the IRE1α-XBP1s branch by regulating NOD2 and its downstream NF-κB and MAPK pathways to induce the production of inflammatory cytokines, which provides a new perspective for the research and development of anti-N. caninum drugs.

Regulatory Functions of Hypoxia in Host-Parasite Interactions: A Focus on Enteric, Tissue, and Blood Protozoa.

Body tissues are subjected to various oxygenic gradients and fluctuations and hence can become transiently hypoxic. Hypoxia-inducible factor (HIF) is the master transcriptional regulator of the cellular hypoxic response and is capable of modulating cellular metabolism, immune responses, epithelial barrier integrity, and local microbiota. Recent reports have characterized the hypoxic response to various infections. However, little is known about the role of HIF activation in the context of protozoan parasitic infections. Growing evidence suggests that tissue and blood protozoa can activate HIF and subsequent HIF target genes in the host, helping or hindering their pathogenicity. In the gut, enteric protozoa are adapted to steep longitudinal and radial oxygen gradients to complete their life cycle, yet the role of HIF during these protozoan infections remains unclear. This review focuses on the hypoxic response to protozoa and its role in the pathophysiology of parasitic infections. We also discuss how hypoxia modulates host immune responses in the context of protozoan infections.

Prevalence of Protozoan and Helminths Parasitic Infection in Palpa, Nepal

In rural areas of underdeveloped countries, the parasitic infestation is a major public health issue for children and the elderly. The purpose of this study was to determine the prevalence of parasite infestations and risk variables related to Palpa parasitic infestations. The population sample was selected from the Tansen area's usual population, as determined by randomized cluster sampling. A total of 700 samples were collected, with 280 persons from urban regions and 420 from rural areas, for a total of 100 people from various categories in each health center. Data were collected for each person based on their age, gender, and place of residence (urban or rural), as well as through a semi-structured questionnaire and a personal interview. Each health center's laboratory technician team conducted the microscopic investigation of samples (blood, urine, and feces). Five protozoal and six helminth parasites were found among the 11 parasites, with eight kinds of gastrointestinal parasites and three species of blood parasites. The most frequent parasites were discovered to be Entamoeba histolytica, Giardia lamblia, and Ascaris lumbricoides. Females and those who live in rural areas are more likely to be parasite-infested. Prevalence was highest among children under the age of 15 and the elderly. Administrators, health experts, and the community need to approve improvements in the living environment and cleaning practices to break the transmission cycle of parasitic illnesses, health education, and community approval.

The Complexity of Interferon Signaling in Host Defense against Protozoan Parasite Infection.

Protozoan parasites, such as Plasmodium, Leishmania, Toxoplasma, Cryptosporidium, and Trypanosoma, are causative agents of health-threatening diseases in both humans and animals, leading to significant health risks and socioeconomic losses globally. The development of effective therapeutic and prevention strategies for protozoan-caused diseases requires a full understanding of the pathogenesis and protective events occurring in infected hosts. Interferons (IFNs) are a family of cytokines with diverse biological effects in host antimicrobial defense and disease pathogenesis, including protozoan parasite infection. Type II IFN (IFN-γ) has been widely recognized as the essential defense cytokine in intracellular protozoan parasite infection, whereas recent studies also revealed the production and distinct function of type I and III IFNs in host defense against these parasites. Decoding the complex network of the IFN family in host-parasite interaction is critical for exploring potential new therapeutic strategies against intracellular protozoan parasite infection. Here, we review the complex effects of IFNs on the host defense against intracellular protozoan parasites and the crosstalk between distinct types of IFN signaling during infections.

Epidemiological study of human diarrhea- causing protozoa in Wasit governorate

The study and Laboratory examinations were performed between (January 2021 and April 2021). We conducted an epidemiological study of intestinal protozoa parasites in the Wasit governorate. The number of samples that collected 500 stool samples in the city center of Kut and Numaniah city. Samples were collected by container from both sexes male and female have the symptom of the infected protozoan parasite, and examined by microscopy with a wet smear method, use a light microscope to detect these protozoan parasites morphologically . We recorded the highest percentage of protozoan parasite infection Entamoeba histolytica (84%) and the lowest percentage of parasite infection Giardia lamblia (16%). The result of laboratory tests showed that males were infected with a higher rate (54%) and the lowest percentage of females (46%). Due to the importance of the intestinal protozoa parasites in the community, this study was encouraging due to the high infection rate.

Toxoplasmosis and symptoms severity in patients with COVID-19 in referral centers in Northern Iran.

Toxoplasmosis has been categorized as one of the long-lasting protozoan parasitic infections. It affects almost one-third of the world's population. In recent years, several documented studies have elucidated that infected individuals have a remarkably higher incidence of distinct health problems and show various adverse effects. In the PCR-positive COVID-19 patients in Gonbad-e-Kavus, Kalaleh, and Minoodasht counties in the northern part of Iran from June 2021 to December 2021, we sought to investigate any potential relationships between the severity of COVID-19 symptoms and acute and latent toxoplasmosis caused by Toxoplasma gondii (T. gondii). Whole blood samples of 161 COVID-19 patients with positive PCR. The samples were centrifuged to separate serum and screened for two important antibodies against T. gondii (IgM and IgG) by using ELISA kits for human anti-T. gondii IgM and IgG. Anti-T. gondii IgM and IgG antibodies were detected in 8/161 (5.0%) and 42/161 (26.1%) COVID-19 patients, respectively. No significant relationships were found between Toxoplasma IgM and IgG results with clinical signs, age, sex, contact with animals, comorbidities, and also the mortality rate of people with COVID-19. These findings showed that acute and latent toxoplasmosis infections are common among patients with COVID-19; however, no significant associations were found between toxoplasma infections and the symptoms of COVID-19. Therefore, toxoplasmosis is not considered a risk factor for COVID-19.

Viral endosymbiotic infection of protozoan parasites: How it influences the development of cutaneous leishmaniasis.

Viral endosymbiotic infection of protozoan parasites: How it influences the development of cutaneous leishmaniasis.

The Defensive Interactions of Prominent Infectious Protozoan Parasites: The Host's Complement System.

The complement system exerts crucial functions both in innate immune responses and adaptive humoral immunity. This pivotal system plays a major role dealing with pathogen invasions including protozoan parasites. Different pathogens including parasites have developed sophisticated strategies to defend themselves against complement killing. Some of these strategies include the employment, mimicking or inhibition of host's complement regulatory proteins, leading to complement evasion. Therefore, parasites are proven to use the manipulation of the complement system to assist them during infection and persistence. Herein, we attempt to study the interaction´s mechanisms of some prominent infectious protozoan parasites including Plasmodium, Toxoplasma, Trypanosoma, and Leishmania dealing with the complement system. Moreover, several crucial proteins that are expressed, recruited or hijacked by parasites and are involved in the modulation of the host´s complement system are selected and their role for efficient complement killing or lysis evasion is discussed. In addition, parasite's complement regulatory proteins appear as plausible therapeutic and vaccine targets in protozoan parasitic infections. Accordingly, we also suggest some perspectives and insights useful in guiding future investigations.

Strategies to Decrease the Prevalence of Soil-Transmitted Helminths in Central India.

Background Intestinal parasites are a major public health problem in tropical countries. Over 1.5 billion people are infected with soil-transmitted helminths (STH), of which 225 million are in India. Parasitic infections are associated with poor sanitation, lack of safe potable water, and improper hygiene. Materials and Methods The study was undertaken to ascertain the impact of control strategies, namely open-defecation free drive and mass drug administration of single dose albendazole. Stool samples received at AIIMS Bhopal Microbiology laboratory, across all age groups, were studied for protozoan trophozoites/cysts and helminthic ova. Results Out of 4,620 stool samples, 389 (8.41%) were positive either for protozoal or helminthic infections. Protozoan infections were more common than helminthic infections with Giardia duodenalis infection being the most common, 201 (51.67%), followed by Entamoeba histolytica , 174 (44.73%). The helminthic infections constituted 14 (3.5%) of the positive stool samples with Hookworm ova in 6 (1.5%) cases. Conclusion This study proves that strategies, namely "Swachh Bharat Abhiyan" and "National Deworming Day" started in 2014 and 2015 led to significant reduction of intestinal parasite infections in Central India, with a higher reduction of STH compared with protozoan parasite infection being ascribed to the activity spectrum of albendazole.

Novel Hits for N-Myristoyltransferase Inhibition Discovered by Docking-Based Screening.

N-myristoyltransferase (NMT) inhibitors that were initially developed for treatment of parasitic protozoan infections, including sleeping sickness, malaria, and leismaniasis, have also shown great promise as treatment for oncological diseases. The successful transition of NMT inhibitors, which are currently at preclinical to early clinical stages, toward clinical approval and utilization may depend on the development and design of a diverse set of drug molecules with particular selectivity or pharmacological properties. In our study, we report that a common feature in the inhibitory mechanism of NMT is the formation of a salt bridge between a positively charged chemical group of the small molecule and the negatively charged C-terminus of an enzyme. Based on this observation, we designed a virtual screening protocol to identify novel ligands that mimic this mode of interaction. By screening over 1.1 million structures downloaded from the ZINC database, several hits were identified that displayed NMT inhibitory activity. The stability of the inhibitor-NMT complexes was evaluated by molecular dynamics simulations. The ligands from the stable complexes were tested in vitro and some of them appear to be promising leads for further optimization.