MicroRNAs in helminth parasites: a systematic review

Helminth-derived molecules: pathogenic and pharmacopeial roles

Parasitic helminths, taxonomically comprising trematodes, cestodes, and nematodes, are multicellular invertebrates widely disseminated in nature and have afflicted people continuously for a long time. Helminths play potent roles in the host through generating a variety of novel molecules, including some excretory/secretory products and others that are involved in intracellular material exchange and information transfer as well as the initiation or stimulation of immune and metabolic activation. The helminth-derived molecules have developed powerful and diverse immunosuppressive effects to achieve immune evasion for parasite survival and establish chronic infections. However, they also improve autoimmune and allergic inflammatory responses and promote metabolic homeostasis by promoting metabolic reprogramming of various immune functions, and then inducing alternatively activated macrophages, T helper 2 cells, and regulatory T cells-mediated immune responses. Therefore, a deeper exploration of the immunopathogenic mechanism and immune regulatory mechanisms of helminth-derived molecules exerted in the host is crucial for understanding host-helminth interactions as well as the development of therapeutic drugs for infectious or non-infectious diseases. In this review, we focus on the properties of helminth-derived molecules to give an overview of the most recent scientific knowledge about their pathogenic and pharmacopeial roles in immune-metabolic homeostasis.

MicroRNA-1 Inhibits the Growth of Breast Cancer Cells MDA-MB-231 and MCF-7 Treated with Hydatid Cyst Fluid

Antigens in hydatid cyst fluid (HCF) have been discovered to bear a significant resemblance to antigens present in cancer cells. MicroRNA-1 (miR-1) is a well-known member of the tumor inhibitor miRNA family and has been shown to have pro-apoptotic and tumor-inhibitory functions. This study aimed to evaluate the ability of HCF to prevent breast cancer and to explore the underlying mechanisms that affect cancer cells. For this study, MDA-MB-231 and MCF-7 breast cancer cells were cultured and divided into two groups: one group received HCF treatment and the other group was untreated and served as the control group. The cytotoxicity and cell viability of various HCF concentrations on breast cancer cells were evaluated using the MTT assay. In addition, the expression level of miR-1 in HCF-treated and untreated breast cancer cells was analyzed using qRT-PCR. The study found that HCF treatment reduced the growth of MDA-MB-231 and MCF-7 breast cancer cells, indicating that it was cytotoxic to the cells. Specifically, the IC50 concentration of HCF after 24 hours of treatment was 7.32 µg/mL for MDA-MB-231 cells and 13.63 µg/mL for MCF-7 cells. In addition, qRT-PCR analysis revealed that the expression level of miR-1 was significantly increased in HCF-treated MDA-MB-231 (P=0.0203) and MCF-7 (P=0.0394) cell lines compared to untreated controls. Although HCF has been shown to inhibit the growth of breast cancer cells and to upregulate miR-1, a key tumor suppressor in cancer cells, the specific mechanisms responsible for this effect remain unclear. Further studies are needed to fully understand the molecular pathways underlying HCF's antitumor activity and its potential as a therapeutic agent in cancer therapy.

microRNAs: Critical Players during Helminth Infections

microRNAs (miRNAs) are a group of small non-coding RNAs that regulate gene expression post-transcriptionally through their interaction with the 3' untranslated regions (3' UTR) of target mRNAs, affecting their stability and/or translation. Therefore, miRNAs regulate biological processes such as signal transduction, cell death, autophagy, metabolism, development, cellular proliferation, and differentiation. Dysregulated expression of microRNAs is associated with infectious diseases, where miRNAs modulate important aspects of the parasite-host interaction. Helminths are parasitic worms that cause various neglected tropical diseases affecting millions worldwide. These parasites have sophisticated mechanisms that give them a surprising immunomodulatory capacity favoring parasite persistence and establishment of infection. In this review, we analyze miRNAs in infections caused by helminths, emphasizing their role in immune regulation and its implication in diagnosis, prognosis, and the development of therapeutic strategies.

Differential miRNA expression profiles in the bone marrow of Beagle dogs at different stages of Toxocara canis infection

BACKGROUND

Toxocara canis is distributed worldwide, posing a serious threat to both human and dog health; however, the pathogenesis of T. canis infection in dogs remains unclear. In this study, the changes in microRNA (miRNA) expression profiles in the bone marrow of Beagle dogs were investigated by RNA-seq and bioinformatics analysis.

RESULTS

Thirty-nine differentially expressed (DE) miRNAs (DEmiRNAs) were identified in this study. Among these, four DEmiRNAs were identified at 24 h post-infection (hpi) and all were up-regulated; eight DEmiRNAs were identified with two up-regulated miRNAs and six down-regulated miRNAs at 96 hpi; 27 DEmiRNAs were identified with 13 up-regulated miRNAs and 14 down-regulated miRNAs at 36 days post-infection (dpi). Among these DEmiRNAs, cfa-miR-193b participates in the immune response by regulating the target gene cd22 at 24 hpi. The novel_328 could participate in the inflammatory and immune responses through regulating the target genes tgfb1 and tespa1, enhancing the immune response of the host and inhibiting the infection of T. canis at 96 hpi. In addition, cfa-miR-331 and novel_129 were associated with immune response and self-protection mechanisms at 36 dpi. 20 pathways were significantly enriched by KEGG pathway analysis, most of which were related to inflammatory response, immune response and cell differentiation, such as Cell adhesion molecules (CAMs), ECM-receptor interaction and Focal adhesion.

CONCLUSIONS

These findings suggested that miRNAs of Beagle dog bone marrow play important roles in the pathogenesis of T. canis infection in dogs and provided useful resources to better understand the interaction between T. canis and the hosts.

Modulation of microRNAs and claudin-7 in Caco-2 cell line treated with Blastocystis sp., subtype 3 soluble total antigen

Background

Blastocystis sp., is a eukaryote of the large intestine, which is reported from almost all countries. The pathogenesis of this protist is not clear. The current study aimed to analyze the effects of Blastocystis sp., ST3 soluble total antigen (B3STA) on the microRNAs (miRNAs) involved in the gut permeability and also pro-inflammatory cytokines, occludin, and claudin-7.

Methods

Blastocystis sp., ST3 isolated from stool sample was purified, and its soluble total antigen was extracted using freeze and thawing. The Caco-2 cell line was treated with B3STA for 24 h and the expression levels of mir-16, mir-21, mir-29a, mir-223, and mir-874 were analyzed. In addition, the expression levels of il-8, il-15, occludin, and claudin-7 genes were assessed.

Results

B3STA significantly upregulated the expression of mir-223, and mir-874, and downregulated mir-29a. The expression of mir-16 and mir-21 was not significant. In addition, the expression of il-8 and il-15 was not significant. B3STA significantly decreased the expression level of claudin-7 (P-value < 0.0001), but the expression of occludin was not significant. Our results showed significant correlation between all studied miRNAs, except mir-29a, with downregulation of claudin-7.

Conclusions

This is the first study investigating the effects of Blastocystis sp., ST3 isolated from symptomatic subjects on the expression levels of miRNAs involved in the gut permeability. Our results demonstrated that B3STA may change miRNA expression, which are involved in the gut barrier integrity, and downregulates claudin-7, which is known as sealing factor.