Characterisation of infection associated microRNA and protein cargo in extracellular vesicles of Theileria annulata infected leukocytes.

The protozoan parasites Theileria annulata and Theileria parva are unique amongst intracellular eukaryotic pathogens as they induce a transformation-like phenotype in their bovine host cell. T. annulata causes tropical theileriosis, which is frequently fatal, with infected leukocytes becoming metastatic and forming foci in multiple organs resulting in destruction of the lymphoid system.

Increased Expression of a MicroRNA Correlates with Anthelmintic Resistance in Parasitic Nematodes.

Resistance to anthelmintic drugs is a major problem in the global fight against parasitic nematodes infecting humans and animals. While previous studies have identified mutations in drug target genes in resistant parasites, changes in the expression levels of both targets and transporters have also been reported. The mechanisms underlying these changes in gene expression are unresolved.

Characterization of HSP90 isoforms in transformed bovine leukocytes infected with Theileria annulata.

HSP90 chaperones are essential regulators of cellular function, as they ensure the appropriate conformation of multiple key client proteins. Four HSP90 isoforms were identified in the protozoan parasite Theileria annulata. Partial characterization was undertaken for three and localization confirmed for cytoplasmic (TA12105), endoplasmic reticulum (TA06470), and apicoplast (TA10720) forms.

Hsp90 Inhibitors in Parasitic Nematodes: Prospects and Challenges.

Hsp90 inhibitors are well characterized in relation to their effects in a variety of tumors, with several inhibitors in various phases of clinical development. In recent years, the same inhibitor classes have been tested for efficacy in other systems, such as Alzheimer's disease and a variety of infectious disease models, including fungal and parasitic targets. In this article we discuss the repurposing of Hsp90 inhibitors for parasitic disease with a focus on parasitic nematode infections.

Application of small RNA technology for improved control of parasitic helminths.

Over the last decade microRNAs (miRNAs) and small interfering RNAs (siRNAs) have emerged as important regulators of post-transcriptional gene expression. miRNAs are short, non-coding RNAs that regulate a variety of processes including cancer, organ development and immune function. This class of small RNAs bind with partial complementarity to their target mRNA sequences, most often in the 3'UTR, to negatively regulate gene expression.

A novel member of the let-7 microRNA family is associated with developmental transitions in filarial nematode parasites.

Background: Filarial nematodes are important pathogens in the tropics transmitted to humans via the bite of blood sucking arthropod vectors. The molecular mechanisms underpinning survival and differentiation of these parasites following transmission are poorly understood. microRNAs are small non-coding RNA molecules that regulate target mRNAs and we set out to investigate whether they play a role in the infection event.

microRNAs of parasitic helminths - Identification, characterization and potential as drug targets.

microRNAs (miRNAs) are small non-coding RNAs involved in post-transcriptional gene regulation. They were first identified in the free-living nematode Caenorhabditis elegans, where the miRNAs lin-4 and let-7 were shown to be essential for regulating correct developmental progression. The sequence of let-7 was subsequently found to be conserved in higher organisms and changes in expression of let-7, as well as other miRNAs, are associated with certain cancers, indicating important regulatory roles.

Nematode Hsp90: highly conserved but functionally diverse.

Nematodes are amongst the most successful and abundant organisms on the planet with approximately 30 000 species described, although the actual number of species is estimated to be one million or more. Despite sharing a relatively simple and invariant body plan, there is considerable diversity within the phylum. Nematodes have evolved to colonize most ecological niches, and can be free-living or can parasitize plants or animals to the detriment of the host organism.

A repurposing strategy for Hsp90 inhibitors demonstrates their potency against filarial nematodes.

Novel drugs are required for the elimination of infections caused by filarial worms, as most commonly used drugs largely target the microfilariae or first stage larvae of these infections. Previous studies, conducted in vitro, have shown that inhibition of Hsp90 kills adult Brugia pahangi. As numerous small molecule inhibitors of Hsp90 have been developed for use in cancer chemotherapy, we tested the activity of several novel Hsp90 inhibitors in a fluorescence polarization assay and against microfilariae and adult worms of Brugia in vitro.

Assay strategies for the discovery and validation of therapeutics targeting Brugia pahangi Hsp90.

The chemotherapy of lymphatic filariasis relies upon drugs such as diethylcarbamazine and ivermectin that largely target the microfilarial stages of the parasite, necessitating continued treatment over the long reproductive life span of the adult worm. The identification of compounds that target adult worms has been a long-term goal of WHO. Here we describe a fluorescence polarization assay for the identification of compounds that target Hsp90 in adult filarial worms.

Hsp-90 and the biology of nematodes.

Background: Hsp-90 from the free-living nematode Caenorhabditis elegans is unique in that it fails to bind to the specific Hsp-90 inhibitor, geldanamycin (GA). Here we surveyed 24 different free-living or parasitic nematodes with the aim of determining whether C. elegans Hsp-90 was the exception or the norm amongst the nematodes.

Functional genomics of hsp-90 in parasitic and free-living nematodes.

Heat shock protein 90 (Hsp-90) is a highly conserved essential protein in eukaryotes. Here we describe the molecular characterisation of hsp-90 from three nematodes, the free-living Caenorhabditis elegans (Ce) and the parasitic worms Brugia pahangi (Bp) and Haemonchus contortus (Hc). These molecules were functionally characterised by rescue of a Ce-daf-21 (hsp-90) null mutant.

The E6E7 oncoproteins of cutaneous human papillomavirus type 38 interfere with the interferon pathway.

Non-melanoma skin cancer is the most frequent malignancy in Caucasian populations. Evidence suggests the involvement of cutaneous Human Papillomavirus (HPV) of the genus beta (beta) in this disease. The ability of E6 and E7 of mucosal HPV to promote cellular transformation and inhibit immune response-related pathways plays a key role in cervical carcinogenesis.

Regulatory T cells modulate Th2 responses induced by Brugia pahangi third-stage larvae.

Infection of BALB/c mice with Brugia pahangi third-stage larvae (L3) results in the production of interleukin-4 (IL-4), IL-5, and IL-10 with a resultant down-regulation in Th1 responses. Previously, this was thought to reflect a skewing of immune responses towards a Th2 phenotype by the infective stage of the parasite. In this study, we show that exposure to the L3 of Brugia also induces the expansion of a population of CD4 cells that express CD25 and cytotoxic-T-lymphocyte-associated antigen 4 in an IL-4-independent fashion.

B cells play a regulatory role in mice infected with the L3 of Brugia pahangi.

Mice infected with the L3 of the filarial nematode Brugia pahangi make a strong T(h)2 response characterized by elevated levels of antigen-specific IL-4, IL-5 and IL-10. Here we show that B cells from these animals are the major proliferating population in vitro with depletion of B cells or infection of muMT mice, resulting in reduced levels of antigen-specific proliferation. B cells also act as antigen-presenting cells (APC) to CD4(+) cells as demonstrated by the switch in cytokine profiles upon B cell depletion.

Mosquito transmission modulates the immune response in mice infected with the L3 of Brugia pahangi.

Mice infected by syringe inoculation with the L3 of the filarial nematode Brugia pahangi generate a strong Th2 response. In this study we compared immune responses in mice infected via syringe with those infected by mosquito transmission of L3. Levels of antigen-specific IL-4, IL-5 and IL-10 were significantly reduced in mice infected via mosquito.

Interleukin-4 influences the production of microfilariae in a mouse model of Brugia infection.

Sub-cutaneous infection of interleukin (IL)-4-/- mice on the BALB/c background with third stage larva (L3) of Brugia pahangi revealed an altered cytokine profile consistent with the absence of the Th2 promoting cytokine IL-4. Splenocytes from IL-4-/- mice secreted significantly more antigen (Ag)-specific IL-2 and interferon-gamma and significantly less Ag-specific IL-5, compared to those from L3-infected wild-type mice. However, levels of Ag-specific IL-13 were similar between groups.