miRNA and circRNA expression patterns in mouse brain during toxoplasmosis development

Expression profile of microRNAs in bovine lymphocytes infected with Theileria annulata and treated with buparvaquone

Several miRNA-based studies on Theileria-transformed bovine cells have been conducted; however, the mechanism by which transformed cells exhibit uncontrolled proliferation is not yet fully understood. Therefore, it is necessary to screen more microRNAs that may play a role in the transformation process of host cells infected with Theileria annulata to better understand the transformation mechanisms of Theileria-infected cells. RNA sequencing was used to analyze miRNAs expression in the host bovine lymphocytes infected with T. annulata at different time points after buparvaquone (BW720) treatment and DMSO treatment (control groups). Differential miRNAs related to cell proliferation and apoptosis were identified through comparison with gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, and a regulatory network of miRNA-mRNA was constructed. In total, 272 differentially expressed miRNAs were found at 36, 60 and 72 h. The miRNAs change of bta-miR-2285t, novel-miR-622, bta-miR-2478, and novel-miR-584 were significant. Analysis of 27 of these co-differential expressed miRNAs revealed that 15 miRNAs were down-regulated and 12 miRNAs were up-regulated. A further analysis of the changes in the expression of each of these 27 miRNAs in the three datasets suggested that bta-miR-2285t, bta-miR-345-5p, bta-miR-34a, bta-miR-150, and the novel-miR-1372 had significantly changed. Predicted target genes for these 27 miRNAs were analyzed by KEGG and the results demonstrated that EZR, RASSF, SOCS1 were mainly enriched in the signaling pathway microRNAs in cancer. MAPKAPK2, RELB, FLT3LG, and GADD45B were mainly enriched in the MAPK signaling pathway, and some genes were enriched in Axon guidance. This study has provided valuable information to further the understanding of the regulatory function of miRNAs in the host microenvironment and host-parasite interaction mechanisms.

miRNA, New Perspective to World of Intestinal Protozoa and Toxoplasma

BACKGROUND

miRNAs are known as non-coding RNAs that can regulate gene expression. They are reported in many microorganisms and their host cells. Parasite infection can change or shift host miRNAs expression, which can aim at both parasite eradication and infection.

PURPOSE

This study dealt with examination of miRNA expressed in intestinal protozoan, coccidia , as well as profile changes in host cell miRNA after parasitic infection and their role in protozoan clearance/ survival.

METHODS

The authors searched ISI Web of Sciences, Pubmed, Scholar, Scopus, another databases and articles published up to 2024 were included. The keywords of miRNA, intestinal protozoa, toxoplasma and some words associated with topics were used in this search.

RESULTS

Transfection of miRNA mimics or inhibitors can control parasitic diseases, and be introduced as a new therapeutic option in parasitology.

CONCLUSION

This review can be used to provide up-to date knowledge for future research on these issues.

The impact of miRNA-155 in acute and chronic toxoplasmosis in Iraqi women

Toxoplasmosis is a prevalent parasitic infection caused by Toxoplasma gondii known to induce complex immune responses, to control the infection. MicroRNAs (miRNAs) are a cluster of small noncoding RNAs that are reported to have regulatory functions in the immune response. The objective of this study is to assess the expression of miR-155 and its targets, Src homology-2 domain-containing inositol 5- phosphatase 1 (SHIP-1) and suppressor of cytokine signaling-1 (SOCS1), in non-pregnant Iraqi women seropositive for toxoplasmosis. The study included 55 non-pregnant women positive for toxoplasmosis (20 in the acute phase and 35 in the chronic phase) and 35 non-pregnant women negative for toxoplasmosis (control group). Serum samples were collected from all participants to investigate the expression of miR-155 by RT‒PCR, in addition to the levels of SOCS1 and SHIP-1 measured by ELISA. The results showed a significant increase in the expression of miR-155 in both groups of acute and chronic toxoplasmosis compared to the control group. Lower levels of SOCS1 and SHIP-1 were found in acutely infected women compared to those with chronic infection and non-infected women. These findings showed the possible critical impact of miR-155 on host immune response during T.gondii infection, proposing that miR-155 can be explored as a prospective target to support host immune response against infectious diseases, with special help in early detection and management of toxoplasmosis in high-risk immunocompromised patients. Further studies are needed to evaluate the molecular pathways by which miRNAs improve immunity against toxoplasmosis.

The role of microRNA-142a in Toxoplasma gondii infection-induced downregulation of Foxp3: implications for adverse pregnancy outcomes

BACKGROUND

Toxoplasma gondii (T. gondii) is capable of infecting nearly all warm-blooded animals and approximately 30% of the global population. Though most infections are subclinical in immunocompetent individuals, congenital contraction can lead to severe consequences such as spontaneous abortion, stillbirth, and a range of cranio-cerebral and/or ocular abnormalities. Previous studies reported that T. gondii-infected pregnancy mice unveiled a deficit in both the amount and suppressive functions of regulatory T (Treg) cells, accompanied with reduced levels of forkhead box p3 (Foxp3). Recently, accumulative studies have demonstrated that microRNAs (miRNAs) are, to some extent, relevant to T. gondii infection. However, the link between alterations in miRNAs and downregulation of Foxp3 triggered by T. gondii has been only sporadically studied.

METHODS

Quantitative reverse transcription polymerase chain reaction (RT-qPCR), protein blotting and immunofluorescence were employed to evaluate the impact of T. gondii infection and antigens on miRNA transcription and Foxp3 expression. Dual-luciferase reporter gene assays were performed to examine the fluorescence activity in EL4 cells, which were transfected with recombinant plasmids containing full-length/truncated/mutant microRNA-142a-3p (miR-142a) promoter sequence or wild type/mutant of Foxp3 3' untranslated region (3' UTR).

RESULTS

We found a pronounced increase in miR-142a transcription, concurrent with a decrease in Foxp3 expression in T. gondii-infected mouse placental tissue. Similarly, comparable findings have been experimentally confirmed through the treatment of EL4 cells with T. gondii antigens (TgAg) in vitro. Simultaneously, miR-142a mimics attenuated Foxp3 expression, whereas its inhibitors markedly augmented Foxp3 expression. miR-142a promoter activity was elevated upon the stimulation of T. gondii antigens, which mitigated co-transfection of mutant miR-142a promoter lacking P53 target sites. miR-142a mimics deceased the fluorescence activity of Foxp3 3' untranslated region (3' UTR), but it did not affect the fluorescence activity upon the co-transfection of mutant Foxp3 3' UTR lacking miR-142a target site.

CONCLUSION

In both in vivo and in vitro studies, a negative correlation was discovered between Foxp3 expression and miR-142a transcription. TgAg enhanced miR-142a promoter activity to facilitate miR-142a transcription through a P53-dependent mechanism. Furthermore, miR-142a directly targeted Foxp3 3' UTR, resulting in the downregulation of Foxp3 expression. Therefore, harnessing miR-142a may be a possible therapeutic approach for adverse pregnancy caused by immune imbalances, particularly those induced by T. gondii infection.

Regulatory mechanism of circular RNAs in neurodegenerative diseases

BACKGROUND

Neurodegenerative disease is a collective term for a category of diseases that are caused by neuronal dysfunction, such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). Circular RNAs (circRNAs) are a class of non-coding RNAs without the 3' cap and 5' poly(A) and are linked by covalent bonds. CircRNAs are highly expressed in brain neurons and can regulate the pathological process of neurodegenerative diseases by affecting the levels of various deposition proteins.

AIMS

This review is aiming to suggest that the majority of circRNAs influence neurodegenerative pathologies mainly by affecting the abnormal deposition of proteins in neurodegenerative diseases.

METHODS

We systematically summarized the pathological features of neurodegenerative diseases and the regulatory mechanisms of circRNAs in various types of neurodegenerative diseases.

RESULTS

Neurodegenerative disease main features include intercellular ubiquitin-proteasome system abnormalities, changes in cytoskeletal proteins, and the continuous deposition of insoluble protein fragments and inclusion bodies in the cytoplasm or nucleus, resulting in impairment of the normal physiological processes of the neuronal system. CircRNAs have multiple mechanisms, such as acting as microRNA sponges, binding to proteins, and regulating transcription. CircRNAs, which are highly stable molecules, are expected to be potential biomarkers for the pathological detection of neurodegenerative diseases such as AD and PD.

CONCLUSIONS

In this review, we describe the regulatory roles and mechanisms of circRNAs in neurodegenerative diseases and aim to employ circRNAs as biomarkers for the diagnosis and treatment of neurodegenerative diseases.

Exosomal miR-222-3p contributes to castration-resistant prostate cancer by activating mTOR signaling

Despite the clinical benefits of androgen deprivation therapy, most patients with advanced androgen-dependent prostate cancer (ADPC) eventually relapse and progress to lethal androgen-independent prostate cancer (AIPC), also termed castration-resistant prostate cancer (CRPC). MiRNAs can be packaged into exosomes (Exos) and shuttled between cells. However, the roles and mechanisms of exosomal miRNAs involved in CRPC progression have not yet been fully elucidated. Here, we find that miR-222-3p is elevated in AIPC cells, which results in remarkable enhancement of cell proliferation, migration, and invasion ability. Furthermore, Exos released by AIPC cells can be uptaken by ADPC cells, thus acclimating ADPC cells to progressing to more aggressive cell types in vitro and in vivo through exosomal transfer of miR-222-3p. Mechanistically, Exos-miR-222-3p promoted ADPC cells transformed to AIPC-like cells, at least in part, by activating mTOR signaling through targeting MIDN. Our results show that AIPC cells secrete Exos containing miRNA cargo. These cargos can be transferred to ADPC cells through paracrine mechanisms that have a strong impact on cellular functional remodeling. The current work underscores the great therapeutic potential of targeting Exo miRNAs, either as a single agent or combined with androgen receptor pathway inhibitors for CRPC treatment.

Functional analysis of differentially expressed circular RNAs in sheep subcutaneous fat

BACKGROUND

Circular RNAs (circRNAs), as important non-coding RNAs (ncRNAs), are involved in many biological activities. However, the exact chemical mechanism behind fat accumulation is unknown. In this paper, we obtained the expression profiles of circRNAs using high-throughput sequencing and investigated their differential expression in subcutaneous fat tissue of Duolang and Small Tail Han sheep.

RESULTS

From the transcriptomic analysis, 141 differentially expressed circRNAs were identified, comprising 61 up-regulated circRNAs and 80 down-regulated circRNAs. These host genes were primarily enriched in the MAPK and AMPK signaling pathways which is closely associated with fat deposition regulation. We identified circRNA812, circRNA91, and circRNA388 as vital genes in fat deposition by miRNA-circRNA target gene prediction. The functional annotation results of target genes of key circRNAs showed that the signaling pathways mainly included PI3K-Akt and AMPK. We constructed the competing endogenous RNA (ceRNA) regulatory network to study the role of circRNAs in sheep lipid deposition, and circRNA812, circRNA91, and circRNA388 can adsorb more miRNAs. NC_040253.1_5757, as the source of miRNA response element (MRE) among the three, may play an important role during the process of sheep fat deposition.

CONCLUSIONS

Our study gives a systematic examination of the circRNA profiles expressed in sheep subcutaneous fat. These results from this study provide some new basis for understanding circRNA function and sheep fat metabolism.

A Systematic Review of Apicomplexa Looking into Epigenetic Pathways and the Opportunity for Novel Therapies

Interest in host epigenetic changes during apicomplexan infections increased in the last decade, mainly due to the emergence of new therapies directed to these alterations. This review aims to carry out a bibliometric analysis of the publications related to host epigenetic changes during apicomplexan infections and to summarize the main studied pathways in this context, pointing out those that represent putative drug targets. We used four databases for the article search. After screening, 116 studies were included. The bibliometric analysis revealed that the USA and China had the highest number of relevant publications. The evaluation of the selected studies revealed that Toxoplasma gondii was considered in most of the studies, non-coding RNA was the most frequently reported epigenetic event, and host defense was the most explored pathway. These findings were reinforced by an analysis of the co-occurrence of keywords. Even though we present putative targets for repurposing epidrugs and ncRNA-based drugs in apicomplexan infections, we understand that more detailed knowledge of the hosts' epigenetic pathways is still needed before establishing a definitive drug target.

Advances and Challenges in Diagnostics of Toxoplasmosis in HIV-Infected Patients

Toxoplasma gondii is a worldwide distributed protozoan parasite. This apicomplexan parasite infects one-third of the population worldwide, causing toxoplasmosis, considered one of the neglected parasitic infections. In healthy humans, most infections are asymptomatic. However, in immunocompromised patients, the course of the disease can be life-threatening. Human immunodeficiency virus (HIV)-infected patients have a very high burden of Toxoplasma gondii co-infection. Thus, it is essential to use modern, sensitive, and specific methods to properly monitor the course of toxoplasmosis in immunodeficient patients.

A combined miRNA-piRNA signature in the serum and urine of rabbits infected with Toxoplasma gondii oocysts

BACKGROUND

Increasing evidence has shown that non-coding RNA (ncRNA) molecules play fundamental roles in cells, and many are stable in body fluids as circulating RNAs. Study on these ncRNAs will provide insights into toxoplasmosis pathophysiology and/or help reveal diagnostic biomarkers.

METHODS

We performed a high-throughput RNA-Seq study to comprehensively profile the microRNAs (miRNAs) and PIWI-interacting RNAs (piRNAs) in rabbit serum and urine after infection with Toxoplasma gondii oocysts during the whole infection process.

RESULTS

Total RNA extracted from serum and urine samples of acutely infected [8 days post-infection (DPI)], chronically infected (70 DPI) and uninfected rabbits were subjected to genome-wide small RNA sequencing. We identified 2089 miRNAs and 2224 novel piRNAs from the rabbit sera associated with T. gondii infection. Meanwhile, a total of 518 miRNAs and 4182 novel piRNAs were identified in the rabbit urine associated with T. gondii infection. Of these identified small ncRNAs, 1178 and 1317 serum miRNAs and 311 and 294 urine miRNAs were identified as differentially expressed (DE) miRNAs in the acute and chronic stages of infections, respectively. A total of 1748 and 1814 serum piRNAs and 597 and 708 urine piRNAs were found in the acute and chronic infection stages, respectively. Of these dysregulated ncRNAs, a total of 88 common DE miRNAs and 120 DE novel piRNAs were found in both serum and urine samples of infected rabbits.

CONCLUSIONS

These findings provide valuable data for revealing the physiology of herbivore toxoplasmosis caused by oocyst infection. Circulating ncRNAs identified in this study are potential novel diagnostic biomarkers for the detection/diagnosis of toxoplasmosis in herbivorous animals.

CircRNA and miRNA expression analysis in livers of mice with Toxoplasma gondii infection

Toxoplasmosis is an important zoonotic parasitic disease caused by Toxoplasma gondii (T. gondii). However, the functions of circRNAs and miRNAs in response to T. gondii infection in the livers of mice at acute and chronic stages remain unknown. Here, high-throughput RNA sequencing was performed for detecting the expression of circRNAs and miRNAs in livers of mice infected with 20 T. gondii cysts at the acute and chronic stages, in order to understand the potential molecular mechanisms underlying hepatic toxoplasmosis. Overall, 265 and 97 differentially expressed (DE) circRNAs were found in livers at the acute and chronic infection stages in comparison with controls, respectively. In addition, 171 and 77 DEmiRNAs were found in livers at the acute and chronic infection stages, respectively. Functional annotation showed that some immunity-related Gene ontology terms, such as “positive regulation of cytokine production”, “regulation of T cell activation”, and “immune receptor activity”, were enriched at the two infection stages. Moreover, the pathways “Valine, leucine, and isoleucine degradation”, “Fatty acid metabolism”, and “Glycine, serine, and threonine metabolism” were involved in liver disease. Remarkably, DEcircRNA 6:124519352|124575359 was significantly correlated with DEmiRNAs mmu-miR-146a-5p and mmu-miR-150-5p in the network that was associated with liver immunity and pathogenesis of disease. This study revealed that the expression profiling of circRNAs in the livers was changed after T. gondii infection, and improved our understanding of the transcriptomic landscape of hepatic toxoplasmosis in mice.

Toxoplasma gondii causes changes in the host's expression of cancer‑associated miRNAs

Throughout the world, numerous individuals are infected with Toxoplasma gondii, which may improve immunity against cancer. Furthermore, microRNAs (miRs) may be differentially expressed in the host upon infection with T. gondii. In the present study, RNA-sequencing analysis and reverse transcription-quantitative PCR revealed that miR-429-3p, miR-145a-5p, miR-211-5p, miR-31-3p and miR-135a-5p were determined to be downregulated, while miR-21a-3p, miR-135b-5p, miR-210-5p and miR-146-3p were upregulated in mice post-infection with T. gondii. Antitumor genes [TNF receptor superfamily member 11b, large tumor suppressor kinase (Lats)2 and Lats1] were identified as targets of miR-429-3p, miR-145a-5p, miR-211-5p, miR-31-3p and miR-135a-5p with a luciferase reporter assay. In addition, the protein levels of Lats2 and Lats1 were detected to be higher in T. gondii-infected mice than in the control group. Therefore, these results provide favorable evidence for the suppression of cancer upon T. gondii infection and may give novel ideas for the treatment of tumors.

Global MicroRNAs Expression Profile Analysis Reveals Possible Regulatory Mechanisms of Brain Injury Induced by Toxoplasma gondii Infection

Toxoplasma gondii (T. gondii) is an obligate intracellular parasitic protozoan that can cause toxoplasmosis in humans and other endotherms. T. gondii can manipulate the host gene expression profile by interfering with miRNA expression, which is closely associated with the molecular mechanisms of T. gondii-induced brain injury. However, it is unclear how T. gondii manipulates the gene expression of central nervous system (CNS) cells through modulation of miRNA expression in vivo during acute and chronic infection. Therefore, high-throughput sequencing was used to investigate expression profiles of brain miRNAs at 10, 25, and 50 days post-infection (DPI) in pigs infected with the Chinese I genotype T. gondii strain in this study. Compared with the control group 87, 68, and 135 differentially expressed miRNAs (DEMs) were identified in the infected porcine brains at 10, 25, and 50 DPI, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that a large number significantly enriched GO terms and KEGG pathways were found, and were mostly associated with stimulus or immune response, signal transduction, cell death or apoptosis, metabolic processes, immune system or diseases, and cancers. miRNA–gene network analysis revealed that the crucial connecting nodes, including DEMs and their target genes, might have key roles in the interactions between porcine brain and T. gondii. These results suggest that the regulatory strategies of T. gondii are involved in the modulation of a variety of host cell signaling pathways and cellular processes, containing unfolded protein response (UPR), oxidative stress (OS), autophagy, apoptosis, tumorigenesis, and inflammatory responses, by interfering with the global miRNA expression profile of CNS cells, allowing parasites to persist in the host CNS cells and contribute to pathological damage of porcine brain. To our knowledge, this is the first report on miRNA expression profile in porcine brains during acute and chronic T. gondii infection in vivo. Our results provide new insights into the mechanisms underlying T. gondii-induced brain injury during different infection stages and novel targets for developing therapeutic agents against T. gondii.

Temporal transcriptomic changes in long non-coding RNAs and messenger RNAs involved in the host immune and metabolic response during Toxoplasma gondii lytic cycle

Background

Long non-coding RNAs (lncRNAs) are important regulators of various biological and pathological processes, in particular the inflammatory response by modulating the transcriptional control of inflammatory genes. However, the role of lncRNAs in regulating the immune and inflammatory responses during infection with the protozoan parasite Toxoplasma gondii remains largely unknown.

Methods

We performed a longitudinal RNA sequencing analysis of human foreskin fibroblast (HFF) cells infected by T. gondii to identify differentially expressed long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs), and dysregulated pathways over the course of T. gondii lytic cycle. The transcriptome data were validated by qRT-PCR.

Results

RNA sequencing revealed significant transcriptional changes in the infected HFFs. A total of 697, 1234, 1499, 873, 1466, 561, 676 and 716 differentially expressed lncRNAs (DElncRNAs), and 636, 1266, 1843, 2303, 3022, 1757, 3088 and 2531 differentially expressed mRNAs (DEmRNAs) were identified at 1.5, 3, 6, 9, 12, 24, 36 and 48 h post-infection, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of DElncRNAs and DEmRNAs revealed that T. gondii infection altered the expression of genes involved in the regulation of host immune response (e.g., cytokine–cytokine receptor interaction), receptor signaling (e.g., NOD-like receptor signaling pathway), disease (e.g., Alzheimer's disease), and metabolism (e.g., fatty acid degradation).

Conclusions

These results provide novel information for further research on the role of lncRNAs in immune regulation of T. gondii infection.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-05140-3.

MicroRNA-155 contributes to host immunity against Toxoplasma gondii

Toxoplasma gondii is well known to infect almost all avian and mammalian species including humans, with worldwide distribution. This protozoan parasite can cause serious toxoplasmosis, posing with a risk to public health. The role of microRNAs in the pathogenesis of T. gondii has not been well described. The aim of the present study was to investigate the role of microRNA-155 (miR-155) in mediating innate and adaptive immune responses during T. gondii infection in mice models. The survival and parasite burden in T. gondii-infected miR-155^−/− and wild-type (WT) C57BL6 mice were compared. In these two mouse models, ELISA tests were used for analysis of Th1-associated, Th2-associated, and Th17-associated cytokines, and flow cytometry was used for analysis of the subpopulations of NK, NKT, CD8⁺T, CD4⁺T cells and regulatory T cells (Tregs), as well as Ly6Chi inflammatory monocytes and dendritic cells. The lack of miR-155 led to increased parasite burden and decreased survival of infected mice in contrast to WT mice. Innate and adaptive immune responses were reduced in the absence of miR-155, along with decreased proinflammatory mediators, Th-1-associated and Th-2-associated cytokines and accumulation of lymphocyte subpopulations. Also, CD8⁺ T cell exhaustion was also worsened in the absence of miR-155 via targeting of SHIP-1 and SOCS1, showing as up-regulated recruitment of Tregs and expression of PD-1, and down-regulated expression of IFN-γ and TNF-α in CD8⁺ T cells. Our results show that miR-155 is a critical immune regulator for the control of T. gondii infection, suggesting that miR-155 can be explored as a potential molecular target for boosting immunity against T. gondii.

Circular RNA ciRS-7 affects the propagation of Cryptosporidium parvum in HCT-8 cells by sponging miR-1270 to activate the NF-κB signaling pathway

BACKGROUND

Cryptosporidium is an important zoonotic pathogen responsible for severe enteric diseases in humans and animals. However, the molecular mechanisms underlying host and Cryptosporidium interactions are still not clear.

METHODS

To study the roles of circRNAs in host cells during Cryptosporidium infection, the expression profiles of circRNAs in HCT-8 cells infected with C. parvum were investigated using a microarray assay, and the regulatory role of a significantly upregulated circRNA, ciRS-7, was investigated during C. parvum infection.

RESULTS

C. parvum infection caused notable alterations in the expression profiles of circRNAs in HCT-8 cells, and a total of 178 (including 128 up- and 50 downregulated) circRNAs were significantly differentially expressed following C. parvum infection. Among them, ciRS-7 was significantly upregulated and regulated the NF-κB signaling pathway by sponging miR-1270 during C. parvum infection. Furthermore, the ciRS-7/miR-1270/relA axis markedly affected the propagation of C. parvum in HCT-8 cells.

CONCLUSIONS

Our results revealed that ciRS-7 would promote C. parvum propagation by regulating the miR-1270/relA axis and affecting the NF-κB pathway. To the best of our knowledge, this is the first study to investigate the role of circRNA during Cryptosporidium infection, and the findings provide a novel view for implementing control strategies against Cryptosporidium infection.