Regulatory effect of host miR-101b-3p on parasitism of nematode Angiostrongylus cantonensis via superoxide dismutase 3

Infection by the Lungworm Rhabdias pseudosphaerocephala Affects the Expression of Immune-Related microRNAs by Its Co-Evolved Host, the Cane Toad Rhinella marina

Parasites may suppress the immune function of infected hosts using microRNAs (miRNAs) to prevent protein production. Nonetheless, little is known about the diversity of miRNAs and their mode(s) of action. In this study, we investigated the effects of infection by a parasitic lungworm (Rhabdias pseudosphaerocephala) on miRNA and mRNA expression of its host, the invasive cane toad (Rhinella marina). To investigate the cane toad's innate and adaptive immune response to this parasite, we compared miRNA and mRNA expression in naïve toads that had never been infected by lungworms to toads that were infected with lungworms for the first time in their lives, and toads that were infected the second time in their lives (i.e., had two consecutive infections). In total, we identified 101 known miRNAs and 86 potential novel miRNAs. Compared to uninfected and single-infection toads, multiple-infection animals drastically downregulated three miRNAs. These miRNAs were associated with gene pathways related to the immune response, potentially reflecting the immunosuppression of cane toads by their parasites. Infected hosts did not respond with substantially differential mRNA transcription; only one gene was differentially expressed between control and single-infection hosts. Our study suggests that miRNA may play an important role in mediating host-parasite interactions in a system in which an ongoing range expansion by the host has generated substantial divergence in host-parasite interactions.

Identifying the function of novel cross-species microRNAs from the excretory-secretory products of Angiostrongylus cantonensis fifth-stage larvae

BACKGROUND

Angiostrongylus cantonensis is a significant foodborne zoonotic parasite that causes severe neuropathological damage and symptoms in humans. Excretory-secretory products (ESPs) play a pivotal role in elucidating host-parasite interactions and can aid in penetrating host defensive barriers in helminths. Recently, secreted microRNAs have become important research targets for parasite-host communication. In this study, we determined the expression and function of novel microRNAs from A. cantonensis L5 ESPs and evaluated the effect of target microRNAs on the molecular mechanisms of mouse astrocytes.

METHODS

Here, we employed next-generation sequencing (NGS) to establish the secreted microRNAs dataset. Next, we evaluated the effects of AcESPs-microRNAs in A. cantonensis ESPs treated astrocytes.

RESULTS

First, we established the secreted microRNA dataset, and then comprehensively verified the characteristics. Novel microRNAs were initially detected, and their expression was found. Moreover, the prediction results showed that these secreted microRNAs may regulate Wnt and mTOR signaling. Next, the data showed that the AcNOVEL55 microRNA reduced cell apoptosis generation via regulating the RhoA-Rock signaling pathway in A. cantonensis L5 ESPs treated mouse astrocytes. Moreover, we also demonstrated that the AcNOVEL31 microRNA can affect the inflammation activation via regulating the presenilin-1/GSK3B/β-catenin/NF-κB pathway. Finally, the concentrations of secreted IL-6 and IL-12 proteins were downregulated by AcNOVEL31 microRNA by influencing presenilin-1 expression.

CONCLUSION

This is the first study to verify the molecular functions of novel microRNAs secreted by A. cantonensis. The discovery of the microRNA mechanisms by which cross-species parasitic nematodes influence hosts has advanced research on host-parasitic nematode interactions.

Identification of miRNA Associated with Trichomonas gallinae Resistance in Pigeon (Columba livia)

Trichomonas gallinae (T. gallinae) has a great influence on the pigeon industry. Pigeons display different resistance abilities to T. gallinae, so the study of the molecular mechanism of resistance is necessary in breeding disease resistant lines. MiRNA plays important roles in the immune response, but there are still no reports of miRNA regulating trichomonosis resistance. We used small RNA sequencing technology to characterize miRNA profiles in different groups. T. gallinae was nasally inoculated in one day old squabs, and according to the infection status, the groups were divided into control (C), susceptible (S) and tolerant (T) groups. We identified 2429 miRNAs in total, including 1162 known miRNAs and 1267 new miRNAs. In a comparison among the C, S and T groups, the target genes of differentially expressed miRNAs were analyzed via GO and KEGG annotation. The results showed that the target genes were enriched in immune-response-related pathways. This indicated that the differentially expressed miRNAs had a critical influence on T. gallinae infection. Novel_miR_741, which could inhibit the expression of PRKCQ, was down-regulated in the T group compared to the C group. It was proven that a decreased novel_miR_741 expression would increase the expression of PRKCQ and increase the immune response. This study brings new insights into understanding the mechanism of trichomonosis resistance.

CEBPα/miR-101b-3p promotes meningoencephalitis in mice infected with Angiostrongylus cantonensis by promoting microglial pyroptosis

BACKGROUND

Angiostrongylus cantonensis (A. cantonensis) infection can induce acute inflammation, which causes meningoencephalitis and tissue mechanical injury to the brain. Parasite infection-induced microRNAs play important roles in anti-parasite immunity in non-permissive hosts. miR-101b-3p is highly expressed after A. cantonensis infection; however, the role of miR-101b-3p and the transcription regulation of miR-101b-3p in A. cantonensis infection remain poorly characterized.

RESULTS

In the present study, we found that miR-101b-3p inhibition alleviated inflammation infiltration and pyroptosis in A. cantonensis infection. In addition, we found that CCAAT/enhancer-binding protein alpha (CEBPα) directly bound to the - 6-k to - 3.5-k region upstream of miR-101b, and CEBPα activated miR-101b-3p expression in microglia. These data suggest the existence of a novel CEBPα/miR-101b-3p/pyroptosis pathway in A. cantonensis infection. Further investigation verified that CEBPα promotes pyroptosis by activating miR-101b-3p expression in microglia, and microglial pyroptosis further promoted inflammation.

CONCLUSIONS

Our results suggest that a CEBPα/miR-101b-3p/pyroptosis pathway may contribute to A. cantonensis infection-induced inflammation and highlight the pro-inflammatory effect of miR-101b-3p. Video Abstract.

Identification and Expression Profiling of Circulating MicroRNAs in Serum of Cysticercus pisiformis-Infected Rabbits

Cysticercus pisiformis (C. pisiformis), the larval form of Taenia pisiformis, parasitize mainly the liver, omentum and mesentery of rabbits and cause huge economic losses in the rabbit breeding industry. MicroRNA (miRNA), a short non-coding RNA, is widely and stably distributed in the plasma and serum. Numerous data demonstrates that, after parasitic infection, miRNAs become the key regulatory factor for controlling host biological processes. However, the roles of serum miRNAs in C. pisiformis-infected rabbits have not been elucidated. In this study, we compared miRNA expression profiles between the C. pisiformis-infected and healthy rabbit serum using RNA-seq. A total of 192 miRNAs were differentially expressed (fold change ≥ 2 and p < 0.05), including 79 up- and 113 downregulated miRNAs. These data were verified by qRT-PCR (real time quantitative polymerase chain reaction) analysis. Additionally, GO analysis showed that the target genes of these dysregulated miRNAs were most enriched in cellular, single-organism and metabolic processes. KEGG pathway analysis showed that these miRNAs target genes were involved in PI3K-Akt, viral carcinogenesis and B cell receptor signaling pathways. Interestingly, after aligning clean reads to the T. pisiformis genome, four (miR-124-3p_3, miR-124-3p_4, miR-124a and novel-miR1) T. pisiformis-derived miRNAs were found. Of these, novel-miR1was upregulated in different periods after C. pisiformis infection, which was verified qRT-PCR, and pre- novel-miR-1 was amplified from the cysticerci by RT-PCR, implying novel-miR-1 was derived from C. pisiformis and has great potential for the diagnosis of Cysticercosis pisiformis infection. This is the first investigation of miRNA expression profile and function in the serum of rabbits infected by C. pisiformis, providing fundamental data for developing diagnostic targets for Cysticercosis pisiformis.

Overview of host miRNA properties and their association with epigenetics, long non-coding RNAs, and Xeno-infectious factors

MicroRNA-derived structures play impressive roles in various biological processes. So dysregulation of miRNAs can lead to different human diseases. Recent studies have extended our comprehension of the control of miRNA function and features. Here, we overview some remarkable miRNA properties that have potential implications for the miRNA functions, including different variants of a miRNA called isomiRs, miRNA arm selection/arm switching, and the effect of these factors on miRNA target selection. Besides, we review some aspects of miRNA interactions such as the interaction between epigenetics and miRNA (different miRNAs and their related processing enzymes are epigenetically regulated by multiple DNA methylation enzymes. moreover, DNA methylation could be controlled by diverse mechanisms related to miRNAs), direct and indirect crosstalk between miRNA and lnc (Long Non-Coding) RNAs as a further approach to conduct intercellular regulation called "competing endogenous RNA" (ceRNA) that is involved in the pathogenesis of different diseases, and the interaction of miRNA activities and some Xeno-infectious (virus/bacteria/parasite) factors, which result in modulation of the pathogenesis of infections. This review provides some related studies to a better understanding of miRNA involvement mechanisms and overcoming the complexity of related diseases that may be applicable and useful to prognostic, diagnostic, therapeutic purposes and personalized medicine in the future.

Speciation and adaptive evolution reshape antioxidant enzymatic system diversity across the phylum Nematoda

Background

Nematodes have evolved to survive in diverse ecological niches and can be a serious burden on agricultural economy, veterinary medicine, and public health. Antioxidant enzymes in parasitic nematodes play a critical role in defending against host oxidative stress. However, the features of the evolution of antioxidant enzymes in the phylum Nematoda remain elusive.

Results

Here, we systematically investigated the evolution and gene expression of antioxidant enzymes in the genomes of 59 nematodes and transcriptomes of 20 nematodes. Catalase has been independently lost in several orders, suggesting that it is unnecessary for some nematodes. Unlike in mammals, phospholipid hydroperoxide glutathione peroxidase is widely distributed in nematodes, among which it has evolved independently. We found that superoxide dismutase (SOD) has been present throughout nematode evolutionary process, and the extracellular isoform (SOD3) is diverged from the corresponding enzyme in mammals and has undergone duplication and differentiation in several nematodes. Moreover, the evolution of intracellular and extracellular SOD isoforms in filaria strongly indicates that extracellular SOD3 originated from intracellular SOD1 and underwent rapid evolution to form the diversity of extracellular SOD3. We identify a novel putative metal-independent extracellular SOD presenting independently in Steinernema and Strongyloididae lineage that featured a high expression level in Strongyloides larvae. Sequence divergence of SOD3 between parasitic nematodes and their closest free-living nematode, the specifically high expression in the parasitic female stage, and presence in excretory-secretory proteome of Strongyloides suggest that SOD3 may be related with parasitism.

Conclusions

This study advances our understanding of the complex evolution of antioxidant enzymes across Nematoda and provides targets for controlling parasitic nematode diseases.