MicroRNAs (miRNAs) have been shown to be present in plasma, which are remarkably stable, and have been suggested as disease biomarkers. Toxoplasma gondii (T. gondii) is a protozoan parasite that is infective to a wide range of animals and human beings. Previous studies have found that the parasite generated a large number of miRNAs during proliferation and it is known that the spectrum of miRNA expression in the infected hosts is pathogen-specific. To date, there are no reports regarding the application of microRNAs as biomarkers for the early detection of T. gondii infection. In this study, we investigated the expression patterns of 414 murine miRNAs and tested their expression levels in the plasma after T. gondii infection by real-time PCR, with an ultimate purpose of identifying infection-related miRNAs. Three miRNAs in particular, exhibiting prominently elevated expressions, were further validated in a large number of infected mice. The Toxoplasma infection-specific miRNAs were confirmed by comparing their expression levels with those of mice infected with Plasmodium berghei, P. yoelii, P. chabaudi, Cryptosporidium parvum, Mouse hepatitis virus, and Staphylococcus aureus. Among the 414 miRNA candidates identified by a real-time PCR array, 71 were found to be up-regulated in the plasma of T. gondii infected mice. Three of those miRNAs (mmu-miR-712-3p, mmu-miR-511-5p and mmu-miR-217-5p) were prominently expressed in mice infected by both the RH and ME49 strains of T. gondii. Additionally, the elevated expression of these miRNAs was Toxoplasma-specific. The levels of the three miRNAs, mmu-miR-712-3p, mmu-miR-511-5p and mmu-miR-217-5p miRNAs, were found specifically up-regulated in plasma of mice after T. gondii infection.

Erythrocyte invasion by merozoites is an essential step in Plasmodium falciparum infection and leads to subsequent disease pathology. Proteins both on the merozoite surface and secreted from the apical organelles (micronemes, rhoptries and dense granules) mediate the invasion of erythrocytes; some of the molecules have been regarded as targets in the development of an anti-malaria vaccine. Recently, a subgroup of rhoptry neck proteins (PfRON2, PfRON4 and PfRON5) associated with the microneme protein apical membrane antigen AMA1 has been described as components of the moving junction complex that assists merozoite invasion into erythrocytes. However, unlike PfRON2, PfRON4 and PfRON5, the latest study suggested that PfRON3 might be located in the rhoptry bulb and participates in a novel PfRON complex (PfRON2, 3 and 4), but does not form a complex with AMA1. Additionally, the full-length PfRON3 protein possesses three transmembrane regions at the N-terminus, which is highly conserved among RON3 orthologues in the genus Plasmodium, Toxoplasma gondii and Eimeria tenella. Overall, these findings suggest that PfRON3 may play an important role in merozoite invasion into erythrocytes.

Vaccines are the most effective agents to control infections. However, recombinant vaccines often do not elicit strong immune responses. Protein antigens combined with proper adjuvants have been widely used to induce immune responses, especially the humoral immune responses, against various pathogens, including parasites. The extracellular matrix protein mindin has been recognised as an immune facilitator for initiating innate immune responses. It has therefore been expected to be a potentially potent adjuvant in the development of novel vaccines. The aim of this study was to investigate whether mindin could facilitate the induction of antigen-specific immune responses to recombinant antigens (rBAG1, rSRS4 and rSRS9) of Toxoplasma gondii in BALB/c mice. In this study, we explored the adjuvant effect of the recombinant mindin in the generation of specific Th1 and Th2 responses to each of three T. gondii antigens, BAG1, SRS4 and SRS9. All mice in the experimental groups received either antigen alone or in combination with Freund’s adjuvant or with the recombinant mindin. The immune responses after immunisation were measured by ELISA and lymphoproliferative assays. The immunised mice were challenged with live T. gondii tachyzoites, and the protection efficiency was compared between the groups. Our results revealed that mindin as an adjuvant could facilitate the recombinant proteins to efficiently stimulate humoral and cellular responses, including antigen-specific IgG1 and IgG2a, as well as lymphocyte proliferation. Furthermore, significantly improved protection against T. gondii infection was observed in the mindin group compared with that of Freund’s adjuvant and no-adjuvant groups. The extracellular matrix protein mindin can effectively induce antigen-specific humoral and cell-mediated immune responses. Our study provides a valuable basis for the development of an efficient, safe, non-toxic vaccine adjuvant for future use in humans and animals.

Background/Objectives: Disorders of glucose and lipid metabolism can easily lead to metabolic diseases such as hyperlipidemia and diabetes mellitus, with multiple complications. This study evaluated the regulatory effect of purple-grain wheat on glycolipid metabolism. Methods: In this study, we established a hyperlipidemic mouse model by means of a high-fat diet and a type 2 diabetic mouse model using a high-fat and high-sugar diet combined with streptozotocin, and the mice were intervened with 15 g/(kg·d), 7.5 g/(kg·d), and 3.75 g/(kg·d) doses of purple-grain wheat paste (PWP) for 4 and 5 weeks, respectively. Results: The results revealed that PWP reversed the increase in body weight; increased serum high-density lipoprotein cholesterol; and decreased serum total cholesterol, triglycerides, and low-density lipoproteins. In addition, PWP reversed the decrease in body weight and alleviated the sustained increase in blood glucose in type 2 diabetic mice. Conclusions: PWP shows a significant ability to regulate glycolipid levels, which is related to its functional composition and its ability to act as a prebiotic. In conclusion, PWP can be considered a potential functional food for lowering blood glucose and blood lipids.