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RNA Biology Mar 2013miRNAs, a subclass of small regulatory RNAs, are present from ancient unicellular protozoans to parasitic helminths and parasitic arthropods. The miRNA-silencing... (Review)
Review
miRNAs, a subclass of small regulatory RNAs, are present from ancient unicellular protozoans to parasitic helminths and parasitic arthropods. The miRNA-silencing mechanism appears, however, to be absent in a number of protozoan parasites. Protozoan miRNAs and components of their silencing machinery possess features different from other eukaryotes, providing some clues on the evolution of the RNA-induced silencing machinery. miRNA functions possibly associate with neoblast biology, development, physiology, infection and immunity of parasites. Parasite infection can alter host miRNA expression that can favor both parasite clearance and infection. miRNA pathways are, thus, a potential target for the therapeutic control of parasitic diseases.
Topics: Animals; Antiparasitic Agents; Evolution, Molecular; Gene Expression Regulation; Humans; MicroRNAs; Parasites; Parasitic Diseases; RNA Interference; RNA, Helminth; RNA, Protozoan; RNA, Small Nucleolar; Signal Transduction
PubMed: 23392243
DOI: 10.4161/rna.23716 -
Antioxidants & Redox Signaling Aug 2012Parasite survival and virulence relies on effective defenses against reactive oxygen and nitrogen species produced by the host immune system. Peroxiredoxins (Prxs) are... (Review)
Review
SIGNIFICANCE
Parasite survival and virulence relies on effective defenses against reactive oxygen and nitrogen species produced by the host immune system. Peroxiredoxins (Prxs) are ubiquitous enzymes now thought to be central to such defenses and, as such, have potential value as drug targets and vaccine antigens.
RECENT ADVANCES
Plasmodial and kinetoplastid Prx systems are the most extensively studied, yet remain inadequately understood. For many other parasites our knowledge is even less well developed. Through parasite genome sequencing efforts, however, the key players are being discovered and characterized. Here we describe what is known about the biochemistry, regulation, and cell biology of Prxs in parasitic protozoa, helminths, and fungi. At least one Prx is found in each parasite with a sequenced genome, and a notable theme is the common patterns of expression, localization, and functionality among sequence-similar Prxs in related species.
CRITICAL ISSUES
The nomenclature of Prxs from parasites is in a state of disarray, causing confusion and making comparative inferences difficult. Here we introduce a systematic Prx naming convention that is consistent between organisms and informative about structural and evolutionary relationships.
FUTURE DIRECTIONS
The new nomenclature should stimulate the crossfertilization of ideas among parasitologists and with the broader redox research community. The diverse parasite developmental stages and host environments present complex systems in which to explore the variety of roles played by Prxs, with a view toward parlaying what is learned into novel therapies and vaccines that are urgently needed.
Topics: Animals; Humans; Models, Molecular; Parasites; Peroxiredoxins; Protein Folding
PubMed: 22098136
DOI: 10.1089/ars.2011.4404 -
Frontiers in Cellular and Infection... 2020Extracellular vesicles (EVs) are membranous structures formed during biological processes in living organisms. For protozoan parasites, secretion of EVs can occur... (Review)
Review
Extracellular vesicles (EVs) are membranous structures formed during biological processes in living organisms. For protozoan parasites, secretion of EVs can occur directly from the parasite organellar compartments and through parasite-infected or antigen-stimulated host cells in response to and physiological stressors. These secreted EVs characteristically reflect the biochemical features of their parasitic origin and activating stimuli. Here, we review the species-specific morphology and integrity of parasitic protozoan EVs in concurrence with the origin, functions, and internalization process by recipient cells. The activating stimuli for the secretion of EVs in pathogenic protozoa are discoursed alongside their biomolecules and specific immune cell responses to protozoan parasite-derived EVs. We also present some insights on the intricate functions of EVs in the context of protozoan parasitism.
Topics: Animals; Exosomes; Extracellular Vesicles; Host-Parasite Interactions; Parasites; Protozoan Proteins
PubMed: 32923407
DOI: 10.3389/fcimb.2020.00371 -
Frontiers in Cellular and Infection... 2023
Topics: Animals; Parasites; Multiomics; Proteomics
PubMed: 37780851
DOI: 10.3389/fcimb.2023.1281638 -
Acta Tropica Jul 2023Annexins (ANXs) exert different functions in cell biological and pathological processes and are thus known as double or multi-faceted proteins. These sophisticated... (Review)
Review
Annexins (ANXs) exert different functions in cell biological and pathological processes and are thus known as double or multi-faceted proteins. These sophisticated proteins might express on both parasite structure and secretion and in parasite-infected host cells. In addition to the characterization of these pivotal proteins, describing their mechanism of action can be also fruitful in recognizing their roles in the pathogenesis of parasitic infections. Accordingly, this study presents the most prominent ANXs thus far identified and their relevant functions in parasites and infected host cells during pathogenesis, especially in the most important intracellular protozoan parasitic infections including leishmaniasis, toxoplasmosis, malaria and trypanosomiasis. The data provided in this study demonstrate that the helminth parasites most probably express and secret ANXs to develop pathogenesis while the modulation of the host-ANXs could be employed as a crucial strategy by intracellular protozoan parasites. Moreover, such data highlight that the use of analogs of both parasite and host ANX peptides (which mimic or regulate ANXs physiological functions through various strategies) might suggest novel therapeutic insights into the treatment of parasitic infections. Furthermore, due to the prominent immunoregulatory activities of ANXs during most parasitic infections and the expression levels of these proteins in some parasitic infected tissues, such multifunctional proteins might be also potentially relevant as vaccine and diagnostic biomarkers. We also suggest some prospects and insights that could be useful and applicable to form the basis of future experimental studies.
Topics: Animals; Humans; Annexins; Parasitic Diseases; Protozoan Infections; Malaria; Leishmaniasis; Parasites
PubMed: 37172709
DOI: 10.1016/j.actatropica.2023.106942 -
PloS One 2023Associations between genetic variants and susceptibility to infections have long been studied in free-living hosts so as to infer the contemporary evolutionary forces...
Associations between genetic variants and susceptibility to infections have long been studied in free-living hosts so as to infer the contemporary evolutionary forces that shape the genetic polymorphisms of immunity genes. Despite extensive studies of proteins interacting with pathogen-derived ligands, such as MHC (major histocompatilbility complex) or TLR (Toll-like receptors), little is known about the efferent arm of the immune system. Cytokines are signalling molecules that trigger and modulate the immune response, acting as a crucial link between innate and adaptive immunity. In the present study we investigated how genetic variation in cytokines in bank voles Myodes glareolus affects their susceptibility to infection by parasites (nematodes: Aspiculuris tianjensis, Heligmosomum mixtum, Heligmosomoides glareoli) and microparasites (Cryptosporidium sp, Babesia microti, Bartonella sp.). We focused on three cytokines: tumour necrosis factor (TNF), lymphotoxin alpha (LTα), and interferon beta (IFNβ1). Overall, we identified four single nucleotide polymorphisms (SNPs) associated with susceptibility to nematodes: two located in LTα and two in IFNβ1. One of those variants was synonymous, another located in an intron. Each SNP associated with parasite load was located in or next to a codon under selection, three codons displayed signatures of positive selection, and one of purifying selection. Our results indicate that cytokines are prone to parasite-driven selection and that non-coding variants, although commonly disregarded in studies of the genetic background of host-parasite co-evolution, may play a role in susceptibility to infections in wild systems.
Topics: Animals; Parasites; Cytokines; Cryptosporidiosis; Cryptosporidium; Polymorphism, Genetic; Nematoda
PubMed: 36693052
DOI: 10.1371/journal.pone.0258009 -
Journal of Fish Biology Sep 2022As climate change progresses, thermal stress is expected to alter the way that host organisms respond to infections by pathogens and parasites, with consequences for the...
As climate change progresses, thermal stress is expected to alter the way that host organisms respond to infections by pathogens and parasites, with consequences for the fitness and therefore population processes of both host and parasite. The authors used a correlational natural experiment to examine how temperature differences shape the impact of the cestode parasite Schistocephalus solidus on its host, the three-spined stickleback (Gasterosteus aculeatus). Previous laboratory work has found that high temperatures benefit S. solidus while being detrimental to the stickleback. The present study sought to emulate this design in the wild, repeatedly sampling naturally infected and uninfected fish at matched warmer and cooler locations in the Baltic Sea. In this wild study, the authors found little evidence that temperature was associated with the host-parasite interaction. Although infection reduced host condition and reproductive status overall, these effects did not vary with temperature. Host fitness indicators correlated to some extent with temperature, with cooler capture sites associated with larger size but warmer sites with improved reproductive potential. Parasite fitness (prevalence or size) was not correlated with temperature at the capture site. These mismatches between laboratory and field outcomes illustrate how findings from well-controlled laboratory experiments may not fully reflect processes in more variable natural settings. Nonetheless, the findings of this study indicate that temperature can influence host fitness regardless of infection, with potential consequences for both host demography and parasite transmission dynamics in this complex system.
Topics: Animals; Cestoda; Cestode Infections; Fish Diseases; Host-Parasite Interactions; Parasites; Smegmamorpha; Temperature
PubMed: 35598110
DOI: 10.1111/jfb.15107 -
Parasites & Vectors Apr 2018In the field of archaeological parasitology, researchers have long documented the distribution of parasites in archaeological time and space through the analysis of... (Review)
Review
In the field of archaeological parasitology, researchers have long documented the distribution of parasites in archaeological time and space through the analysis of coprolites and human remains. This area of research defined the origin and migration of parasites through presence/absence studies. By the end of the 20th century, the field of pathoecology had emerged as researchers developed an interest in the ancient ecology of parasite transmission. Supporting studies were conducted to establish the relationships between parasites and humans, including cultural, subsistence, and ecological reconstructions. Parasite prevalence data were collected to infer the impact of parasitism on human health. In the last few decades, a paleoepidemiological approach has emerged with a focus on applying statistical techniques for quantification. The application of egg per gram (EPG) quantification methods provide data about parasites' prevalence in ancient populations and also identify the pathological potential that parasitism presented in different time periods and geographic places. Herein, we compare the methods used in several laboratories for reporting parasite prevalence and EPG quantification. We present newer quantification methods to explore patterns of parasite overdispersion among ancient people. These new methods will be able to produce more realistic measures of parasite infections among people of the past. These measures allow researchers to compare epidemiological patterns in both ancient and modern populations.
Topics: Animals; Archaeology; Feces; Fossils; Humans; Mummies; Parasites; Parasitology
PubMed: 29661215
DOI: 10.1186/s13071-018-2729-4 -
Expert Opinion on Drug Discovery Aug 2016Despite the fact that diseases caused by protozoan parasites represent serious challenges for public health, animal production and welfare, only a limited panel of drugs... (Review)
Review
INTRODUCTION
Despite the fact that diseases caused by protozoan parasites represent serious challenges for public health, animal production and welfare, only a limited panel of drugs has been marketed for clinical applications.
AREAS COVERED
Herein, the authors investigate two strategies, namely whole organism screening and target-based drug design. The present pharmacopoeia has resulted from whole organism screening, and the mode of action and targets of selected drugs are discussed. However, the more recent extensive genome sequencing efforts and the development of dry and wet lab genomics and proteomics that allow high-throughput screening of interactions between micromolecules and recombinant proteins has resulted in target-based drug design as the predominant focus in anti-parasitic drug development. Selected examples of target-based drug design studies are presented, and calcium-dependent protein kinases, important drug targets in apicomplexan parasites, are discussed in more detail.
EXPERT OPINION
Despite the enormous efforts in target-based drug development, this approach has not yet generated market-ready antiprotozoal drugs. However, whole-organism screening approaches, comprising of both in vitro and in vivo investigations, should not be disregarded. The repurposing of already approved and marketed drugs could be a suitable strategy to avoid fastidious approval procedures, especially in the case of neglected or veterinary parasitoses.
Topics: Animals; Antiprotozoal Agents; Drug Design; Genomics; High-Throughput Screening Assays; Humans; Molecular Targeted Therapy; Parasites; Proteomics; Protozoan Infections
PubMed: 27238605
DOI: 10.1080/17460441.2016.1195945 -
Biomolecules Apr 2020Studies on the parasite-host interaction may provide valuable information concerning the modulation of molecular mechanisms as well as of the host immune system during... (Review)
Review
Studies on the parasite-host interaction may provide valuable information concerning the modulation of molecular mechanisms as well as of the host immune system during infection. To date, it has been demonstrated that intestinal parasites may affect, among others, the processes of digestion in the gastrointestinal system of the host, thus limiting the elimination of the parasite, the immune response as well as inflammation. However, the most recent studies suggest that intestinal parasites may also affect modulation of the apoptosis pathway of the host. The present paper presents the latest scientific information on the influence of intestinal parasite species ( sp., sp., sp., sp., , , ) on the molecular mechanisms of apoptosis in intestinal epithelial cells. This paper stresses that the interdependency between the intestinal parasite and the host results from the direct effect of the parasite and the host's defense reactions, which lead to modulation of the apoptosis pathways (intrinsic and extrinsic). Moreover, the present paper presents the role of proteins involved in the mechanisms of apoptosis as well as the physiological role of apoptosis in the host's intestinal epithelial cells.
Topics: Animals; Apoptosis; Enterocytes; Host-Parasite Interactions; Humans; Intestinal Diseases, Parasitic; Parasites
PubMed: 32349424
DOI: 10.3390/biom10050674