miR-27b targets KSRP to coordinate TLR4-mediated epithelial defense against Cryptosporidium parvum infection

MEF2C Directly Interacts with Pre-miRNAs and Distinct RNPs to Post-Transcriptionally Regulate miR-23a-miR-27a-miR-24-2 microRNA Cluster Member Expression

Transcriptional regulation constitutes a key step in gene expression regulation. Myocyte enhancer factor 2C (MEF2C) is a transcription factor of the MADS box family involved in the early development of several cell types, including muscle cells. Over the last decade, a novel layer of complexity modulating gene regulation has emerged as non-coding RNAs have been identified, impacting both transcriptional and post-transcriptional regulation. microRNAs represent the most studied and abundantly expressed subtype of small non-coding RNAs, and their functional roles have been widely documented. On the other hand, our knowledge of the transcriptional and post-transcriptional regulatory mechanisms that drive microRNA expression is still incipient. We recently demonstrated that MEF2C is able to transactivate the long, but not short, regulatory element upstream of the miR-23a-miR-27a-miR-24-2 transcriptional start site. However, MEF2C over-expression and silencing, respectively, displayed distinct effects on each of the miR-23a-miR-27a-miR-24-2 mature cluster members without affecting pri-miRNA expression levels, thus supporting additional MEF2C-driven regulatory mechanisms. Within this study, we demonstrated a complex post-transcriptional regulatory mechanism directed by MEF2C in the regulation of miR-23a-miR-27a-miR-24-2 cluster members, distinctly involving different domains of the MEF2C transcription factor and the physical interaction with pre-miRNAs and Ksrp, HnRNPa3 and Ddx17 transcripts.

K-Homology Type Splicing Regulatory Protein: Mechanism of Action in Cancer and Immune Disorders

K homology-type splicing regulatory protein (KSRP) is emerging as a key player in cancer biology, and immunology. As a single-strand nucleic acid binding protein it functions in both transcriptional and post-transcriptional regulation, while facilitating multiple stages of RNA metabolism to affect proliferation and control cell fate. However, it must interact with other proteins to determine the fate of its bound substrate. Here we provide an minireview of this important regulatory protein and describe its complex subcellular functions to affect RNA metabolism, stability, miRNA biogenesis and maturation, stress granule function, metastasis, and inflammatory processes.

MiR-4521 affects the propagation of Cryptosporidium parvum in HCT-8 cells through targeting foxm1 by regulating cell apoptosis

Cryptosporidium parvum could regulate the expression of microRNAs of epithelial cells to facilitate its intracellular propagation. MiR-4521 has been reported to play an important role during the development and progression of tumors and infectious diseases by regulating cell proliferation, apoptosis, and autophagy. However, the implication of miR-4521 during C. parvum infection was still unknown. In this study, the expression of miR-4521 was found to be upregulated in HCT-8 cells infected with C. parvum from 8 h post-infection (pi) to 48 hpi, and its upregulation would be related with the TLR/NF-κB signal pathway during C. parvum infection. One potential target of miR-4521, foxm1, was down-regulated in HCT-8 cells from 24 hpi to 48 hpi, and the expression of foxm1 was negatively regulated by miR-4521. The target relationship between miR-4521 and foxm1 was further validated by using dual luciferase reporter assay. Further studies showed that miR-4521 promoted the propagation of C. parvum in HCT-8 cells through targeting foxm1 by regulating BCL2-mediating cell apoptosis. These results contribute to further understanding of the regulatory mechanisms of host miRNAs during Cryptosporidium infection.

Micro-RNA expression profile of BALB/c mouse glandular stomach in the early phase of Cryptosporidium muris infection

Cryptosporidiosis is a zoonotic disease in humans and animals that is caused by infection with the oocysts of Cryptosporidium. MicroRNAs (miRNAs) are important players in regulating the innate immune response against parasitic infection. Public miRNAs data for studying pathogenic mechanisms of cryptosporidiosis, particularly in natural hosts, are scarce. Here, we compared miRNA profiles of the glandular stomach of C. muris-infected and uninfected BALB/c mice using microarray sequencing. A total of 10 miRNAs (including 3 upregulated and 7 downregulated miRNAs) with significant differential expression (|FC| ≥ 2 and P value < 0.05) were identified in the glandular stomach of BALB/c mice 8 h after infection with C. muris. MiRWalk and miRDB online bioinformatics tools were used to predict the target genes of differentially expressed miRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to annotate the target genes. GO analysis indicate that gene transcription-related and ion transport-related GO terms were significantly enriched. In addition, the KEGG analyses showed that the target genes were strongly related to diverse types of tumor disease progression and anti-pathogen immunity pathways. In the current study, we firstly report changes in miRNA expression profiles in the glandular stomach of BALB/c mice at the early phase of C. muris invasion. This dysregulation in miRNA expression may contribute to our understanding of cryptosporidiosis pathology. This study provides a new perspective on the miRNA regulatory mechanisms of cryptosporidiosis, which may help in the development of effective control strategies against this pathogen.

Cysticercus pisiformis-derived novel-miR1 targets TLR2 to inhibit the immune response in rabbits

Cysticercosis pisiformis, a highly prevalent parasitic disease worldwide, causes significant economic losses in the rabbit breeding industry. Previous investigations have identified a novel microRNA, designated as novel-miR1, within the serum of rabbit infected with Cysticercus pisiformis. In the present study, we found that C. pisiformis-derived novel-miR1 was released into the rabbit serum via exosomes. Through computational analysis using TargetScan, miRanda, and PITA, a total of 634 target genes of novel-miR1 were predicted. To elucidate the functional role of novel-miR1, a dual-luciferase reporter assay was utilized and demonstrated that novel-miR1 targets rabbit Toll-like receptor 2 (TLR2). Rabbit peripheral blood lymphocytes (PBLCs) were transfected with novel-miR1 mimic and mimic NC, and the in vitro experiments confirmed that novel-miR1 suppressed the expression of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6 through the nuclear factor kappa B (NF-κB) pathway. In vivo experiments demonstrated that novel-miR1 was significantly upregulated during the 1-3 months following infection with C. pisiformis in rabbits. Notably, this upregulation coincided with a downregulation of TLR2, P65, pP65, TNF-α, IL-1β, and IL-6 in PBLCs. Collectively, these results indicate that the novel-miR1 derived from C. pisiformis inhibited the rabbits' immune response by suppressing the NF-κB-mediated immune response. This immune modulation facilitates parasite invasion, survival, and establishment of a persistent infection.

MiR-3976 regulates HCT-8 cell apoptosis and parasite burden by targeting BCL2A1 in response to Cryptosporidium parvum infection

BACKGROUND

Cryptosporidium is second only to rotavirus as a cause of moderate-to-severe diarrhea in young children. There are currently no fully effective drug treatments or vaccines for cryptosporidiosis. MicroRNAs (miRNAs) are involved in regulating the innate immune response to Cryptosporidium parvum infection. In this study, we investigated the role and mechanism of miR-3976 in regulating HCT-8 cell apoptosis induced by C. parvum infection.

METHODS

Expression levels of miR-3976 and C. parvum burden were estimated using real-time quantitative polymerase chain reaction (RT-qPCR) and cell apoptosis was detected by flow cytometry. The interaction between miR-3976 and B-cell lymphoma 2-related protein A1 (BCL2A1) was studied by luciferase reporter assay, RT-qPCR, and western blotting.

RESULTS

Expression levels of miR-3976 were decreased at 8 and 12 h post-infection (hpi) but increased at 24 and 48 hpi. Upregulation of miR-3976 promoted cell apoptosis and inhibited the parasite burden in HCT-8 cells after C. parvum infection. Luciferase reporter assay indicated that BCL2A1 was a target gene of miR-3976. Co-transfection with miR-3976 and a BCL2A1 overexpression vector revealed that miR-3976 targeted BCL2A1 and suppressed cell apoptosis and promoted the parasite burden in HCT-8 cells.

CONCLUSIONS

The present data indicated that miR-3976 regulated cell apoptosis and parasite burden in HCT-8 cells by targeting BCL2A1 following C. parvum infection. Future study should determine the role of miR-3976 in hosts' anti-C. parvum immunity in vivo.

Triad3A involved in the regulation of endotoxin tolerance and mycobactericidal activity through the NFκB-nitric oxide pathway

INTRODUCTION

Sepsis is characterized by an endotoxin tolerance phenotype that occurs in the stage of infection. Persistent bacterial infection can lead to immune cell exhaustion. Triad3A, an E3 ubiquitin ligase, negatively regulates its activation by TLR4. However, the effect of Triad3A on endotoxin tolerance and bactericidal ability in the state of endotoxin tolerance remains unclear.

METHODS

Using single dose LPS and repeated LPS stimulated macrophage cell lines at indicated times, we investigated miR-191, Tirad3A, TRAF3, TLR4, p-P65, TNF-α, IL-1β, and iNOS expression, the effect of miR-191 on Triad3A and TRAF3, gene loss-of-function analyses, the effect of Triad3A on TLR4, p-P65, cytokine, and mycobactericidal activity in endotoxin tolerant cells infected with Mycobacterium marinum.

RESULTS

Here we found that Triad3A is involved in regulating endotoxin tolerance. Our result also displayed that miR-191 expression is downregulated in macrophages in the state of endotoxin tolerance. miR-191 can directly bind to Triad3A and TRAF3. Additionally, knockdown of Triad3A can reverse the effect of decreasing TNF-α and IL-1β in endotoxin tolerant macrophages. Furthermore, we demonstrated that the TLR4-NF-κB-NO pathway was associated with Triad3A and responsible for the killing of intracellular mycobacteria in a tuberculosis sepsis model.

CONCLUSIONS

These results provide new insight into the mechanisms of Triad3A induced tolerogenic phenotype in macrophages, which can help the better comprehension of the pathogenesis involved in septic shock with infection of Mycobacterium tuberculosis, and suggest that Triad3A may be a potential drug target for the treatment of severe septic tuberculosis.

Cryptosporidium parvum hijacks a host's long noncoding RNA U90926 to evade intestinal epithelial cell-autonomous antiparasitic defense

Cryptosporidium is a zoonotic apicomplexan parasite that infects the gastrointestinal epithelium and other mucosal surfaces in humans. It is an important opportunistic pathogen in AIDS patients and a leading cause of infectious diarrhea and diarrheal-related death in children worldwide. The intestinal epithelial cells provide the first line of defense against Cryptosporidium infection and play a central role in activating and regulating the host's antiparasitic response. Increasing evidence suggests that long noncoding RNAs (lncRNAs) participate in host-pathogen interactions and play a regulatory role in the pathogenesis of diseases but the underlying molecular mechanisms are not fully understood. We previously identified a panel of host lncRNAs that are upregulated in murine intestinal epithelial cells following Cryptosporidium infection, including U90926. We demonstrate here that U90926 is acting in a pro-parasitic manner in regulating intestinal epithelial cell-autonomous antiparasitic defense. Inhibition of U90926 resulted in a decreased infection burden of the parasite while overexpression of U90926 showed an increase in infection burden in cultured murine intestinal epithelial cells. Induction of U90926 suppressed transcription of epithelial defense genes involved in controlling Cryptosporidium infection through epigenetic mechanisms. Specifically, transcription of Aebp1, which encodes the Aebp1 protein, a potent modulator of inflammation and NF-κB signaling, was suppressed by U90926. Gain- or loss-of-function of Aebp1 in the host's epithelial cells caused reciprocal alterations in the infection burden of the parasite. Interestingly, Cryptosporidium carries the Cryptosporidium virus 1 (CSpV1), a double-stranded (ds) RNA virus coding two dsRNA fragments, CSpV1-dsRdRp and CSpV1-dsCA. Both CSpV1-dsRdRp and CSpV1-dsCA can be delivered into infected cells as previously reported. We found that cells transfected with in vitro transcribed CSpV1-dsCA or CSpV1-dsRdRp displayed an increased level of U90926, suggesting that CSpV1 is involved in the upregulation of U90926 during Cryptosporidium infection. Our study highlights a new strategy by Cryptosporidium to hijack a host lncRNA to suppress epithelial cell-autonomous antiparasitic defense and allow for a robust infection.

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.

Whole transcriptome analysis of HCT-8 cells infected by Cryptosporidium parvum

BACKGROUND

Cryptosporidium species are zoonotic protozoans that are important causes of diarrhoeal disease in both humans and animals. Non-coding RNAs (ncRNAs) play an important role in the innate immune defense against Cryptosporidium infection, but the underlying molecular mechanisms in the interaction between human ileocecal adenocarcinoma (HCT-8) cells and Cryptosporidium species have not been entirely revealed.

METHODS

The expression profiles of messenger RNAs (mRNAs), long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and circular RNAs (circRNAs) in the early phase of infection of HCT-8 cells with Cryptosporidium parvum and at 3 and 12 h post infection were analyzed using the RNA-sequencing technique. The biological functions of differentially expressed RNAs (dif-RNAs) were discovered through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. The targeting relationships between three ncRNAs and mRNAs were analyzed using bioinformatics methods, followed by building a competing endogenous RNA (ceRNA) regulatory network centered on miRNAs.

RESULTS

After strictly filtering the raw data, our analysis revealed 393 dif-lncRNAs, 69 dif-miRNAs and 115 dif-mRNAs at 3 hpi, and 450 dif-lncRNAs, 129 dif-miRNAs, 117 dif-mRNAs and one dif-circRNA at 12 hpi. Of these, 94 dif-lncRNAs, 24 dif-miRNAs and 22 dif-mRNAs were detected at both post-infection time points. Eleven dif-lncRNAs, seven dif-miRNAs, eight dif-mRNAs and one circRNA were randomly selected and confirmed using the quantitative real-time PCR. Bioinformatics analyses showed that the dif-mRNAs were significantly enriched in nutritional absorption, metabolic processes and metabolism-related pathways, while the dif-lncRNAs were mainly involved in the pathways related to the infection and pathogenicity of C. parvum (e.g. tight junction protein) and immune-related pathways (e.g. cell adhesion molecules). In contrast, dif-miRNAs and dif-circRNA were significantly enriched in apoptosis and apoptosis-related pathways. Among the downregulated RNAs, the miRNAs has-miR-324-3p and hsa-miR-3127-5p appear to be crucial miRNAs which could negatively regulate circRNA, lncRNA and mRNA.

CONCLUSIONS

The whole transcriptome profiles of HCT-8 cells infected with C. parvum were obtained in this study. The results of the GO and KEGG pathway analyses suggest significant roles for these dif-RNAs during the course of C. parvum infection. A ceRNA regulation network containing miRNA at its center was constructed for the first time, with hsa-miR-324-3p and hsa-miR-3127-5p being the crucial miRNAs. These findings provide novel insights into the responses of human intestinal epithelial cells to C. parvum infection.

MiR-942-5p targeting the IFI27 gene regulates HCT-8 cell apoptosis via a TRAIL-dependent pathway during the early phase of Cryptosporidium parvum infection

BACKGROUND

MicroRNAs (miRNAs) are involved in the regulation of both the innate and adaptive immune response to Cryptosporidium parvum infection. We previously reported that C. parvum upregulated miR‑942‑5p expression in HCT‑8 cells via TLR2/TLR4‑NF‑κB signaling. In the present study, the role of miRNA-942-5p in the regulation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated HCT-8 cell apoptosis induced by C. parvum was investigated.

METHODS

Quantitative real-time polymerase chain reaction, western blotting, flow cytometry, and immunofluorescence were used for analysis.

RESULTS

Forced expression of miRNA-942-5p resulted in decreased apoptosis and an increased C. parvum burden in HCT-8 cells. The opposite results were observed using the suppressed expression of miRNA-942-5p. The miRNA-942-5p led to the translational suppression of IFI27 gene through targeting the 3'-untranslated region of the IFI27 gene. Moreover, overexpression of the IFI27 gene produced a high apoptotic ratio and low C. parvum burden. In contrast, a low apoptotic ratio and a high C. parvum burden were observed following downregulation of the IFI27 gene. Both miR-942-5p and the IFI27 gene influenced TRAIL and caspase-8 expression induced by C. parvum in HCT-8 cells. Moreover, TRAIL promoted HCT-8 cell apoptosis in a concentration-dependent manner.

CONCLUSIONS

These data suggested that C. parvum induced the downregulation of IFI27 via relief of miR-942-5p-mediated translational suppression. IFI27 downregulation was affected the burden of C. parvum by regulating HCT-8 cell apoptosis through TRAIL-dependent pathways. Future studies should determine the mechanisms by which C. parvum infection increases miR-942-5p expression and the role of miR-942-5p in hosts' anti-C. parvum immunity in vivo.

Cryptosporidium and colorectal cancer: a review of epidemiology and possible association

Cryptosporidiosis is an important protozoan disease with serious public health implications. The contribution of Cryptosporidium to colorectal cancer is still vaguely studied, but little evidence from experimental and epidemiological studies has suggested a possible association. This review discusses the epidemiology of cryptosporidiosis and colorectal cancer and attempts to unravel the possible link between the two diseases using epidemiological, pathological, molecular, and immunological evidence. The review stressed the need to undertake more studies in this relatively neglected field.

The Role of KH-Type Splicing Regulatory Protein (KSRP) for Immune Functions and Tumorigenesis

Post-transcriptional control of gene expression is one important mechanism that enables stringent and rapid modulation of cytokine, chemokines or growth factors expression, all relevant for immune or tumor cell function and communication. The RNA-binding protein KH-type splicing regulatory protein (KSRP) controls the mRNA stability of according genes by initiation of mRNA decay and inhibition of translation, and by enhancing the maturation of microRNAs. Therefore, KSRP plays a pivotal role in immune cell function and tumor progression. In this review, we summarize the current knowledge about KSRP with regard to the regulation of immunologically relevant targets, and the functional role of KSRP on immune responses and tumorigenesis. KSRP is involved in the control of myeloid hematopoiesis. Further, KSRP-mediated mRNA decay of pro-inflammatory factors is necessary to keep immune homeostasis. In case of infection, functional impairment of KSRP is important for the induction of robust immune responses. In this regard, KSRP seems to primarily dampen T helper cell 2 immune responses. In cancer, KSRP has often been associated with tumor growth and metastasis. In summary, aside of initiation of mRNA decay, the KSRP-mediated regulation of microRNA maturation seems to be especially important for its diverse biological functions, which warrants further in-depth examination.

The Long Non-Coding RNA Nostrill Regulates Transcription of Irf7 Through Interaction With NF-κB p65 to Enhance Intestinal Epithelial Defense Against Cryptosporidium parvum

The cells of the intestinal epithelium establish the frontline for host defense against pathogens in the gastrointestinal tract and play a vital role in the initiation of the immune response. Increasing evidence supports the role of long non-coding RNAs (lncRNAs) as critical regulators of diverse cellular processes, however, their role in antimicrobial host defense is incompletely understood. In this study, we provide evidence that the lncRNA Nostrill is upregulated in the intestinal epithelium following infection by Cryptosporidium parvum, a globally prevalent apicomplexan parasite that causes significant diarrheal disease and an important opportunistic pathogen in the immunocompromised and AIDS patients. Induction of Nostrill in infected intestinal epithelial cells was triggered by NF-κB signaling and was observed to enhance epithelial defense by decreasing parasitic infection burden. Nostrill participates in the transcriptional regulation of C. parvum-induced Irf7 expression through interactions with NF-κB p65, and induction of Nostrill promotes epigenetic histone modifications and occupancy of RNA polymerase II at the Irf7 promoter. Our data suggest that the induction of Nostrill promotes antiparasitic defense against C. parvum and enhances intestinal epithelial antimicrobial defense through contributions to transcriptional regulation of immune-related genes, such as Irf7.

A Bioinformatics Approach to Identifying Potential Biomarkers for Cryptosporidium parvum: A Coccidian Parasite Associated with Fetal Diarrhea

Cryptosporidium parvum (C. parvum) is a protozoan parasite known for cryptosporidiosis in pre-weaned calves. Animals and patients with immunosuppression are at risk of developing the disease, which can cause potentially fatal diarrhoea. The present study aimed to construct a network biology framework based on the differentially expressed genes (DEGs) of C. parvum infected subjects. In this way, the gene expression profiling analysis of C. parvum infected individuals can give us a snapshot of actively expressed genes and transcripts under infection conditions. In the present study, we have analyzed microarray data sets and compared the gene expression profiles of the patients with the different data sets of the healthy control. Using a network medicine approach to identify the most influential genes in the gene interaction network, we uncovered essential genes and pathways related to C. parvum infection. We identified 164 differentially expressed genes (109 up- and 54 down-regulated DEGs) and allocated them to pathway and gene set enrichment analysis. The results underpin the identification of seven significant hub genes with high centrality values: ISG15, MX1, IFI44L, STAT1, IFIT1, OAS1, IFIT3, RSAD2, IFITM1, and IFI44. These genes are associated with diverse biological processes not limited to host interaction, type 1 interferon production, or response to IL-gamma. Furthermore, four genes (IFI44, IFIT3, IFITM1, and MX1) were also discovered to be involved in innate immunity, inflammation, apoptosis, phosphorylation, cell proliferation, and cell signaling. In conclusion, these results reinforce the development and implementation of tools based on gene profiles to identify and treat Cryptosporidium parvum-related diseases at an early stage.

LncRNA XR_001779380 Primes Epithelial Cells for IFN-γ-Mediated Gene Transcription and Facilitates Age-Dependent Intestinal Antimicrobial Defense

Interferon (IFN) signaling is key to mucosal immunity in the gastrointestinal tract, but cellular regulatory elements that determine interferon gamma (IFN-γ)-mediated antimicrobial defense in intestinal epithelial cells are not fully understood. We report here that a long noncoding RNA (lncRNA), GenBank accession no. XR_001779380, was increased in abundance in murine intestinal epithelial cells following infection by Cryptosporidium, an important opportunistic pathogen in AIDS patients and a common cause of diarrhea in young children. Expression of XR_001779380 in infected intestinal epithelial cells was triggered by TLR4/NF-κB/Cdc42 signaling and epithelial-specific transcription factor Elf3. XR_001779380 primed epithelial cells for IFN-γ-mediated gene transcription through facilitating Stat1/Swi/Snf-associated chromatin remodeling. Interactions between XR_001779380 and Prdm1, which is expressed in neonatal but not adult intestinal epithelium, attenuated Stat1/Swi/Snf-associated chromatin remodeling induced by IFN-γ, contributing to suppression of IFN-γ-mediated epithelial defense in neonatal intestine. Our data demonstrate that XR_001779380 is an important regulator in IFN-γ-mediated gene transcription and age-associated intestinal epithelial antimicrobial defense. IMPORTANCE Epithelial cells along the mucosal surface provide the front line of defense against luminal pathogen infection in the gastrointestinal tract. These epithelial cells represent an integral component of a highly regulated communication network that can transmit essential signals to cells in the underlying intestinal mucosa that, in turn, serve as targets of mucosal immune mediators. LncRNAs are recently identified long noncoding transcripts that can regulate gene transcription through their interactions with other effect molecules. In this study, we demonstrated that lncRNA XR_001779380 was upregulated in murine intestinal epithelial cells following infection by a mucosal protozoan parasite Cryptosporidium. Expression of XR_001779380 in infected cells primed host epithelial cells for IFN-γ-mediated gene transcription, relevant to age-dependent intestinal antimicrobial defense. Our data provide new mechanistic insights into how intestinal epithelial cells orchestrate intestinal mucosal defense against microbial infection.

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.

Effects of colostrum management on transfer of passive immunity and the potential role of colostral bioactive components on neonatal calf development and metabolism

Neonatal dairy and beef calves are required to ingest adequate volumes of high-quality colostrum during their first hours of life to acquire transfer of passive immunity (TPI). As such, immunoglobulin G (IgG) has largely been the focus of colostrum research over recent decades. Yet, little is known about the additional bioactive compounds in colostrum that potentially influence newborn calf development and metabolism. The purpose of this narrative review is to synthesize research regarding the effects of colostrum management practices on TPI, as well as to address the potential role of additional colostral bioactive molecules, including oligosaccharides, fatty acids, insulin, and insulin-like growth factor-I, in promoting calf development and metabolism. Due to the importance of IgG in ensuring calf immunity and health, we review past research describing the process of colostrogenesis and dam factors influencing the concentrations of IgG in an effort to maximize TPI. We also address the transfer of additional bioactive compounds in colostrum and prepartum management and dam factors that influence their concentrations. Finally, we highlight key areas of future research for the scientific community to pursue to ultimately improve the health and welfare of neonatal dairy calves.

m6A mRNA Methylation Regulates Epithelial Innate Antimicrobial Defense Against Cryptosporidial Infection

Increasing evidence supports that N6-methyladenosine (m⁶A) mRNA modification may play an important role in regulating immune responses. Intestinal epithelial cells orchestrate gastrointestinal mucosal innate defense to microbial infection, but underlying mechanisms are still not fully understood. In this study, we present data demonstrating significant alterations in the topology of host m⁶A mRNA methylome in intestinal epithelial cells following infection by Cryptosporidium parvum, a coccidian parasite that infects the gastrointestinal epithelium and causes a self-limited disease in immunocompetent individuals but a life-threatening diarrheal disease in AIDS patients. Altered m⁶A methylation in mRNAs in intestinal epithelial cells following C. parvum infection is associated with downregulation of alpha-ketoglutarate-dependent dioxygenase alkB homolog 5 and the fat mass and obesity-associated protein with the involvement of NF-кB signaling. Functionally, m⁶A methylation statuses influence intestinal epithelial innate defense against C. parvum infection. Specifically, expression levels of immune-related genes, such as the immunity-related GTPase family M member 2 and interferon gamma induced GTPase, are increased in infected cells with a decreased m⁶A mRNA methylation. Our data support that intestinal epithelial cells display significant alterations in the topology of their m⁶A mRNA methylome in response to C. parvum infection with the involvement of activation of the NF-кB signaling pathway, a process that modulates expression of specific immune-related genes and contributes to fine regulation of epithelial antimicrobial defense.

Expression analysis of circulating miR-146a and miR-155 as novel biomarkers related to effective immune responses in human cystic echinococcosis

Cystic echinococcosis, an important zoonotic disease, is caused by Echinococcus granulosus. MicroRNAs are a small group of single-stranded noncoding RNAs, which play an effective role in biological processes. This study aimed at comparing the expression levels of miR-146a and miR-155 in the plasma of patients with hydatidosis and healthy individuals. A group of 20 patients with hydatid cyst formed a study group and 20 healthy individuals with no known chronic diseases formed a control group. Plasma samples were collected from hydatidosis patients as well as sex- and age-matched healthy volunteers. After that, RNA extraction and cDNA synthesis were done and the expression levels of miR-146a and miR-155 were determined by quantitative real-time polymerase chain reaction (PCR) for both groups. The results indicated that the level of miR-146a increased in all patients with hydatidosis compared to the control group. Also, the level of miR-155 increased in all hydatidosis patients, but no correlation was observed in the level of miR-155 between the two groups. The results also revealed that miR-146a and miR-155 upregulation in the plasma leads to the development of novel biomarkers for echinococcosis. One of the reasons for the increase of miRNAs in hydatidosis may be their role in modulating the immune system. These miRNAs are likely to be considered as one of the most important biomarkers in determining the severity of hydatidosis.

Cryptosporidial Infection Suppresses Intestinal Epithelial Cell MAPK Signaling Impairing Host Anti-Parasitic Defense

Cryptosporidium is a genus of protozoan parasites that infect the gastrointestinal epithelium of a variety of vertebrate hosts. Intestinal epithelial cells are the first line of defense and play a critical role in orchestrating host immunity against Cryptosporidium infection. To counteract host defense response, Cryptosporidium has developed strategies of immune evasion to promote parasitic replication and survival within epithelial cells, but the underlying mechanisms are largely unclear. Using various models of intestinal cryptosporidiosis, we found that Cryptosporidium infection caused suppression of mitogen-activated protein kinase (MAPK) signaling in infected murine intestinal epithelial cells. Whereas expression levels of most genes encoding the key components of the MAPK signaling pathway were not changed in infected intestinal epithelial cells, we detected a significant downregulation of p38/Mapk, MAP kinase-activated protein kinase 2 (Mk2), and Mk3 genes in infected host cells. Suppression of MAPK signaling was associated with an impaired intestinal epithelial defense against C. parvum infection. Our data suggest that cryptosporidial infection may suppress intestinal epithelial cell MAPK signaling associated with the evasion of host antimicrobial defense.

Human microRNAs in host-parasite interaction: a review

MicroRNAs (miRNAs) are a group of small noncoding RNA molecules with significant capacity to regulate the gene expression at the post-transcriptional level in a sequence-specific manner either through translation repression or mRNA degradation triggering a fine-tuning biological impact. They have been implicated in several processes, including cell growth and development, signal transduction, cell proliferation and differentiation, metabolism, apoptosis, inflammation, and immune response modulation. However, over the last few years, extensive studies have shown the relevance of miRNAs in human pathophysiology. Common human parasitic diseases, such as Malaria, Leishmaniasis, Amoebiasis, Chagas disease, Schistosomiasis, Toxoplasmosis, Cryptosporidiosis, Clonorchiasis, and Echinococcosis are the leading cause of death worldwide. Thus, identifying and characterizing parasite-specific miRNAs and their host targets, as well as host-related miRNAs, are important for a deeper understanding of the pathophysiology of parasite-specific diseases at the molecular level. In this review, we have demonstrated the impact of human microRNAs during host-parasite interaction as well as their potential to be used for diagnosis and prognosis purposes.

The emerging role of microRNAs in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection

The novel coronavirus disease 2019 (COVID-19) pandemic has imposed significant public health problems for the human populations worldwide after the 1918 influenza A virus (IVA) (H1N1) pandemic. Although numerous efforts have been made to unravel the mechanisms underlying the coronavirus, a notable gap remains in our perception of the COVID-19 pathogenesis. The innate and adaptive immune systems have a pivotal role in the fate of viral infections, such as COVID-19 pandemic. MicroRNAs (miRNAs) are known as short noncoding RNA molecules and appear as indispensable governors of almost any cellular means. Several lines of evidence demonstrate that miRNAs participate in essential mechanisms of cell biology, regulation of the immune system, and the onset and progression of numerous types of disorders. The immune responses to viral respiratory infections (VRIs), including influenza virus (IV), respiratory syncytial virus (RSV), and rhinovirus (RV), are correlated with the ectopic expression of miRNAs. Alterations of the miRNA expression in epithelial cells may contribute to the pathogenesis of chronic and acute airway infections. Hence, analyzing the role of these types of nucleotides in antiviral immune responses and the characterization of miRNA target genes might contribute to understanding the mechanisms of the interplay between the host and viruses, and in the future, potentially result in discovering therapeutic strategies for the prevention and treatment of acute COVID-19 infection. In this article, we present a general review of current studies concerning the function of miRNAs in different VRIs, particularly in coronavirus infection, and address all available therapeutic prospects to mitigate the burden of viral infections.

Cryptosporidium parvum upregulates miR-942-5p expression in HCT-8 cells via TLR2/TLR4-NF-κB signaling

Background

Micro (mi)RNAs are small noncoding RNA molecules that function in RNA silencing and post-transcriptional regulation of gene expression. This study investigated host miRNA activity in the innate immune response to Cryptosporidium parvum infection.

Methods

In vitro infection model adopts HCT-8 human ileocecal adenocarcinoma cells infected with C. parvum. The expression of miR-942-5p was estimated using quantitative real-time polymerase chain reaction (qPCR). The TLRs-NF-κB signaling was confirmed by qPCR, western blotting, TLR4- and TLR2-specific short-interfering (si)RNA, and NF-κB inhibition.

Results

HCT-8 cells express all known toll-like receptors (TLRs). Cryptosporidium parvum infection of cultured HCT-8 cells upregulated TLR2 and TLR4, and downstream TLR effectors, including NF-κB and suppressed IκBα (nuclear factor of kappa light polypeptide gene enhancer in B cells inhibitor, alpha). The expression of miR-942-5p was significantly upregulated at 4, 8, 12 and 24 h post-infection, and especially at 8 hpi. The results of TLR4- and TLR2-specific siRNA and NF-κB inhibition showed that upregulation of miR-942-5p was promoted by p65 subunit-dependent TLR2/TLR4-NF-κB pathway signaling.

Conclusions

miR-942-5p of HCT-8 cells was significantly upregulated after C. parvum infection, especially at 8 hpi, in response to a p65-dependent TLR2/TLR4-NF-κB signaling. TLR4 appeared to play a dominant role.

Lack of TLR4 modifies the miRNAs profile and attenuates inflammatory signaling pathways

TLR4 is a member of the toll-like receptors (TLR) immune family, which are activated by lipopolysaccharide, ethanol or damaged tissue, among others, by triggering proinflammatory cytokines release and inflammation. Lack of TLR4 protects against inflammatory processes and neuroinflammation linked with several neuropathologies. By considering that miRNAs are key post-transcriptional regulators of the proteins involved in distinct cellular processes, including inflammation, this study aimed to assess the impact of the miRNAs profile in mice cortices lacking the TLR4 response. Using mice cerebral cortices and next-generation sequencing (NGS), the findings showed that lack of TLR4 significantly reduced the quantity and diversity of the miRNAs expressed in WT mice cortices. The results also revealed a significant down-regulation of the miR-200 family, while cluster miR-99b/let-7e/miR-125a was up-regulated in TLR4-KO vs. WT. The bioinformatics and functional analyses demonstrated that TLR4-KO presented the systematic depletion of many pathways closely related to the immune system response, such as cytokine and interleukin signaling, MAPK and ion Channels routes, MyD88 pathways, NF-κβ and TLR7/8 pathways. Our results provide new insights into the molecular and biological processes associated with the protective effects of TLR-KO against inflammatory damage and neuroinflammation, and reveal the relevance of the TLR4 receptors response in many neuropathologies.

MiR-27b-3p suppresses glioma development via targeting YAP1

Previous studies have reported that miRNAs are involved in the progression of glioma, and that miR-27b-3p is involved in a variety of cancers. However, whether miR-27b-3p has a role in glioma is still unknown. Here, we demonstrated that miR-27b-3p is downregulated in glioma, and this is associated with the development of glioma. Overexpression of miR-27b-3p in glioma cells inhibits cell proliferation and migration, and induces cell apoptosis, which suppresses the progression of glioma. Furthermore, in our study, overexpression of miR-27b-3p also inhibited the growth of xenografted glioma tumors in-vivo. Finally, we verified that Yes Associated Protein 1 (YAP1) is the downstream target of miR-27b-3p, and that miR-27b-3p controls the proliferation, migration, and apoptosis of glioma cells via regulating YAP1. Our study reveals a novel mechanism through which miR-27b-3p functions in the development of glioma, and thus provides a potential therapeutic target for the treatment of glioma.

Replacement of forage fiber with non-forage fiber sources in dairy cow diets changes milk extracellular vesicle-miRNA expression

Milk is a dynamic source of nutrients and bioactive factors, varying with the nutrition status of the cattle. We partly replaced alfalfa hay with whole cotton seed and soybean hull (non-forage fiber source, NFFS) in the feed formula of treated cows and evaluated the effects on milk extracellular vesicles (EVs). The NFFS supplement did not affect the shape of milk EVs observed using a transmission electron microscope. Nanoparticle tracking analysis revealed that the EV concentration increased significantly in treated cows (P = 0.019), with the peak diameter unaffected by the treatment. The EV-RNA concentration and small RNA content, particularly rRNAs and tRNAs, significantly increased in the treated cows (P < 0.05). The other small RNAs, i.e. miRNAs, cis-regulatory elements, snRNAs, and other Rfam RNAs showed no significant difference between the two groups. Totally 276 milk EV-miRNAs were identified. Thirteen miRNAs, accounting for 76%, in the highly expressed top 20, were immune-related. In addition, 9 differently expressed miRNAs (4 up-regulated and 5 down-regulated) were identified (P < 0.05). Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the differently expressed miRNAs were related to the citrate cycle, fat digestion and absorption process, taurine and hypo-taurine metabolism, and glycosphingolipid biosynthesis. This study documents the milk nutrition assessment from macromolecules, especially EVs.

Upregulation of KSRP by miR-27b attenuates schistosomiasis-induced hepatic fibrosis by targeting TGF-β1

Hepatic stellate cells (HSCs) are the main effectors for various types of hepatic fibrosis, including Schistosome-induced hepatic fibrosis. Multiple inflammatory cytokines/chemokines, such as transforming growth factor-β1 (TGF-β1), activate HSCs, and contribute to the development of hepatic fibrosis. MicroRNAs regulate gene expression at the posttranscriptional level and are involved in regulation of inflammatory cytokine/chemokine synthesis. In this study, we showed that soluble egg antigen (SEA) stimulation and Schistosoma japonicum infection downregulate miR-27b expression and increase KH-type splicing regulatory protein (KSRP) mRNA and protein levels in vitro and in vivo. miR-27b regulates the stabilization of TGF-β1 mRNA through targeting KSRP by interacting with their AU-rich elements in hepatocytes and non-parenchymal cells, which has an effect on the activation of HSCs. Importantly, our results have shown that either knockdown miR-27b or overexpression of KSRP attenuates S. japonicum-induced hepatic fibrosis in vivo. Therefore, our study highlights the crucial role of miR-27b and KSRP in the negative regulation of immune reactions in hepatocyte and non-parenchymal cells in response to SEA stimulation and S. japonicum infection. It reveals that manipulation of miR-27b or KSRP might be a useful strategy not only for treating Schistosome-induced hepatic fibrosis but also for curing hepatic fibrosis in general.

Induction of Inflammatory Responses in Splenocytes by Exosomes Released from Intestinal Epithelial Cells following Cryptosporidium parvum Infection

Cryptosporidium, a protozoan parasite that infects the gastrointestinal epithelium and other mucosal surfaces in humans and animals, is an important opportunistic pathogen in AIDS patients and one of the most common enteric pathogens affecting young children in developing regions. This parasite is referred to as a "minimally invasive" mucosal pathogen, and epithelial cells play a central role in activating and orchestrating host immune responses. We previously demonstrated that Cryptosporidium parvum infection stimulates host epithelial cells to release exosomes, and these released exosomes shuttle several antimicrobial peptides to carry out anti-C. parvum activity. In this study, we detected the upregulation of inflammatory genes in the liver and spleen following C. parvum intestinal infection in neonatal mice. Interestingly, exosomes released from intestinal epithelial cells following C. parvum infection could activate the nuclear factor kappa B signaling pathway and trigger inflammatory gene transcription in isolated primary splenocytes. Several epithelial cell-derived proteins and a subset of parasite RNAs were detected in the exosomes released from C. parvum-infected intestinal epithelial cells. Shuttling of these effector molecules, including the high mobility group box 1 protein, was involved in the induction of inflammatory responses in splenocytes induced by the exosomes released from infected cells. Our data indicate that exosomes released from intestinal epithelial cells upon C. parvum infection can activate immune cells by shuttling various effector molecules, a process that may be relevant to host systemic responses to Cryptosporidium infection.

Involvement of Cryptosporidium parvum Cdg7_FLc_1000 RNA in the Attenuation of Intestinal Epithelial Cell Migration via Trans-Suppression of Host Cell SMPD3

Intestinal infection by Cryptosporidium parvum causes inhibition of epithelial turnover, but underlying mechanisms are unclear. Previous studies demonstrate that a panel of parasite RNA transcripts of low protein-coding potential are delivered into infected epithelial cells. Using in vitro and in vivo models of intestinal cryptosporidiosis, we report here that host delivery of parasite Cdg7_FLc_1000 RNA results in inhibition of epithelial cell migration through suppression of the gene encoding sphingomyelinase 3 (SMPD3). Delivery of Cdg7_FLc_1000 into infected cells promotes the histone methyltransferase G9a-mediated H3K9 methylation in the SMPD3 locus. The DNA-binding transcriptional repressor, PR domain zinc finger protein 1, is required for the assembly of Cdg7_FLc_1000 into the G9a complex and associated with the enrichment of H3K9 methylation at the gene locus. Pathologically, nuclear transfer of Cryptosporidium parvum Cdg7_FLc_1000 RNA is involved in the attenuation of intestinal epithelial cell migration via trans-suppression of host cell SMPD3.

MicroRNA expression profile of HCT-8 cells in the early phase of Cryptosporidium parvum infection

Background

Cryptosporidium parvum is an important zoonotic parasitic disease worldwide, but the molecular mechanisms of the host–parasite interaction are not fully understood. Noncoding microRNAs (miRNAs) are considered key regulators of parasitic diseases. Therefore, we used microarray, qPCR, and bioinformatic analyses to investigate the intestinal epithelial miRNA expression profile after Cryptosporidium parvum infection.

Results

Twenty miRNAs were differentially expressed after infection (four upregulated and 16 downregulated). Further analysis of the differentially expressed miRNAs revealed that many important cellular responses were triggered by Cryptosporidium parvum infection, including cell apoptosis and the inflammatory and immune responses.

Conclusions

This study demonstrates for the first time that the miRNA expression profile of human intestinal epithelium cells is altered by C. parvum infection. This dysregulation of miRNA expression may contribute to the regulation of host biological processes in response to C. parvum infection, including cell apoptosis and the immune responses. These results provide new insight into the regulatory mechanisms of host miRNAs during cryptosporidiosis, which may offer potential targets for future C. parvum control strategies.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5410-6) contains supplementary material, which is available to authorized users.

Induction of a Long Noncoding RNA Transcript, NR_045064, Promotes Defense Gene Transcription and Facilitates Intestinal Epithelial Cell Responses against Cryptosporidium Infection

Cryptosporidium is an important opportunistic intestinal pathogen for immunocompromised individuals and a common cause of diarrhea in young children in developing countries. Gastrointestinal epithelial cells play a central role in activating and orchestrating host immune responses against Cryptosporidium infection, but underlying molecular mechanisms are not fully understood. We report in this paper that C. parvum infection causes significant alterations in long noncoding RNA (lncRNA) expression profiles in murine intestinal epithelial cells. Transcription of a panel of lncRNA genes, including NR_045064, in infected cells is controlled by the NF-κB signaling. Functionally, inhibition of NR_045064 induction increases parasite burden in intestinal epithelial cells. Induction of NR_045064 enhances the transcription of selected defense genes in host cells following C. parvum infection. Epigenetic histone modifications are involved in NR_045064-mediated transcription of associated defense genes in infected host cells. Moreover, the p300/MLL-associated chromatin remodeling is involved in NR_045064-mediated transcription of associated defense genes in intestinal epithelial cells following C. parvum infection. Expression of NR_045064 and associated genes is also identified in intestinal epithelium in C57BL/6J mice following phosphorothioate oligodeoxynucleotide or LPS stimulation. Our data demonstrate that lncRNAs, such as NR_045064, play a role in regulating epithelial defense against microbial infection.

Attenuation of Intestinal Epithelial Cell Migration During Cryptosporidium parvum Infection Involves Parasite Cdg7_FLc_1030 RNA-Mediated Induction and Release of Dickkopf-1

Intestinal infection by Cryptosporidium is known to cause epithelial cell migration disorder but the underlying mechanisms are unclear. Previous studies demonstrated that a panel of parasite RNA transcripts of low protein-coding potential are delivered into infected epithelial cells. Using multiple models of intestinal cryptosporidiosis, we report here that C. parvum infection induces expression and release of the dickkopf protein 1 (Dkk1) from intestinal epithelial cells. Delivery of parasite Cdg7_FLc_1030 RNA to intestinal epithelial cells triggers transactivation of host Dkk1 gene during C. parvum infection. Release of Dkk1 is involved in C. parvum-induced inhibition of cell migration of epithelial cells, including noninfected bystander cells. Moreover, Dkk1-mediated suppression of host cell migration during C. parvum infection involves inhibition of Cdc42/Par6 signaling. Our data support the hypothesis that attenuation of intestinal epithelial cell migration during Cryptosporidium infection involves parasite Cdg7_FLc_1030 RNA-mediated induction and release of Dkk1 from infected cells.

MiR-27a/b Regulates Liver Regeneration by Posttranscriptional Modification of Tmub1

BACKGROUND

Transmembrane and ubiquitin-like domain-containing 1 protein (Tmub1) negatively regulates liver regeneration. However, whether this regulation involves posttranscriptional modification of Tmub1 expression is unknown.

AIM

The aim of the study was to investigate whether microRNA (miR)-27a/b regulates posttranscriptional modification of Tmub1 and cell proliferation during liver regeneration.

METHODS

Tmub1 mRNA 3'-untranslated region (UTR) sequences were analyzed using online software. A luciferase assay was used to verify the relationship between miR-27a/b and the 3'-UTR of Tmub1. Rat partial hepatectomy models were used to investigate miR-27a/b and Tmub1 levels after partial hepatectomy. MiR-27a/b expression was down- and up-regulated with mimics and inhibitors, respectively, to observe the effects of miR-27a/b on Tmub1 expression. Quantitative RT-PCR and Western blot analyses were used to measure miR-27a/b and Tmub1 expression. Hepatocyte proliferation was measured using the CCK8 method for BRL-3A liver cells and proliferating cell nuclear antigen and histone H3 phosphorylation in the regenerating liver.

RESULTS

A potential binding site of miR-27a/b was found in the 3'-UTR sequence of Tmub1. Our luciferase assay confirmed that the Tmub1 mRNA 3'-UTR was the target of miR-27a/b. We observed a temporal correlation between miR-27a/b and Tmub1 expression during liver regeneration. MiR-27a/b down-regulated Tmub1 expression both in vivo and in vitro. MiR-27a/b regulated hepatocyte proliferation during liver regeneration.

CONCLUSION

MiR-27a/b regulates hepatocyte proliferation by controlling posttranscriptional modification of Tmub1 during liver regeneration.

Modelling Cryptosporidium infection in human small intestinal and lung organoids

Stem-cell-derived organoids recapitulate in vivo physiology of their original tissues, representing valuable systems to model medical disorders such as infectious diseases. Cryptosporidium, a protozoan parasite, is a leading cause of diarrhoea and a major cause of child mortality worldwide. Drug development requires detailed knowledge of the pathophysiology of Cryptosporidium, but experimental approaches have been hindered by the lack of an optimal in vitro culture system. Here, we show that Cryptosporidium can infect epithelial organoids derived from human small intestine and lung. The parasite propagates within the organoids and completes its complex life cycle. Temporal analysis of the Cryptosporidium transcriptome during organoid infection reveals dynamic regulation of transcripts related to its life cycle. Our study presents organoids as a physiologically relevant in vitro model system to study Cryptosporidium infection.

MicroRNA-27b Modulates Inflammatory Response and Apoptosis during Mycobacterium tuberculosis Infection

Mycobacterium tuberculosis poses a significant global health threat. MicroRNAs play an important role in regulating host anti-mycobacterial defense; however, their role in apoptosis-mediated mycobacterial elimination and inflammatory response remains unclear. In this study, we explored the role of microRNA-27b (miR-27b) in murine macrophage responses to M. tuberculosis infection. We uncovered that the TLR-2/MyD88/NF-κB signaling pathway induced the expression of miR-27b and miR-27b suppressed the production of proinflammatory factors and the activity of NF-κB, thereby avoiding an excessive inflammation during M. tuberculosis infection. Luciferase reporter assay and Western blotting showed that miR-27b directly targeted Bcl-2-associated athanogene 2 (Bag2) in macrophages. Overexpression of Bag2 reversed miR-27b-mediated inhibition of the production of proinflammatory factors. In addition, miR-27b increased p53-dependent cell apoptosis and the production of reactive oxygen species and decreased the bacterial burden. We also showed that Bag2 interacts with p53 and negatively regulates its activity, thereby controlling cell apoptosis and facilitating bacterial survival. In summary, we revealed a novel role of the miR-27b/Bag2 axis in the regulation of inflammatory response and apoptosis and provide a potential molecular host defense mechanism against mycobacteria.

Trans-suppression of defense DEFB1 gene in intestinal epithelial cells following Cryptosporidium parvum infection is associated with host delivery of parasite Cdg7_FLc_1000 RNA

To counteract host immunity, Cryptosporidium parvum has evolved multiple strategies to suppress host antimicrobial defense. One such strategy is to reduce the production of the antimicrobial peptide beta-defensin 1 (DEFB1) by host epithelial cells but the underlying mechanisms remain unclear. Recent studies demonstrate that a panel of parasite RNA transcripts of low protein-coding potential are delivered into infected host cells and may modulate host gene transcription. Using in vitro models of intestinal cryptosporidiosis, in this study, we analyzed the expression profile of host beta-defensin genes in host cells following infection. We found that C. parvum infection caused a significant downregulation of the DEFB1 gene. Interestingly, downregulation of DEFB1 gene was associated with host delivery of Cdg7_FLc_1000 RNA transcript, a C. parvum RNA that has previously demonstrated to be delivered into the nuclei of infected host cells. Knockdown of Cdg7_FLc_1000 in host cells could attenuate the trans-suppression of host DEFB1 gene and decreased the parasite burden. Therefore, our data suggest that trans-suppression of DEFB1 gene in intestinal epithelial cells following C. parvum infection involves host delivery of parasite Cdg7_FLc_1000 RNA, a process that may be relevant to the epithelial defense evasion by C. parvum at the early stage of infection.

Nuclear delivery of parasite Cdg2_FLc_0220 RNA transcript to epithelial cells during Cryptosporidium parvum infection modulates host gene transcription

Intestinal infection by the zoonotic protozoan, Cryptosporidium parvum, causes significant alterations in the gene expression profile in host epithelial cells. The molecular mechanisms of how C. parvum may modulate host cell gene transcription and the pathological significance of such alterations are largely unclear. Previous studies demonstrate that a panel of parasite RNA transcripts are delivered into infected host cells and may modulate host gene transcription. Using in vitro models of intestinal cryptosporidiosis, in this study, we analyzed the impact of host delivery of C. parvum Cdg2_FLc_0220 RNA transcript on host gene expression profile. We found that alterations in host gene expression profile following C. parvum infection were partially associated with the nuclear delivery of Cdg2_FLc_0220. Specifically, we identified a total of 46 overlapping upregulated genes and 8 overlapping downregulated genes in infected cells and cells transfected with Full-Cdg2_FLc_0220. Trans-suppression of the DAZ interacting zinc finger protein 1 like (DZIP1L) gene, the top overlapping downregulated gene in host cells following C. parvum infection and cells transfected with Full-Cdg2_FLc_0220, was mediated by G9a, independent of PRDM1. Cdg2_FLc_0220-mediated trans-suppression of the DZIP1L gene was independent of H3K9 and H3K27 methylation. Data from this study provide additional evidence that delivery of C. parvum Cdg2_FLc_0220 RNA transcript in infected epithelial cells modulates the transcription of host genes, contributing to the alterations in the gene expression profile in host epithelial cells during C. parvum infection.

Effects of the RNA-binding protein, KSRP, on innate immune response against Helicobacter pylori infection in mice

Helicobacter pylori (H. pylori) contributes to various gastric diseases such as chronic gastritis, gastric ulcer, and gastric carcinoma. Host innate immune response against the pathogen plays a significant role in elimination of pathogen infection. Importantly, pathogen elimination is closely related to numerous inflammatory-related genes that participate in complex biological response of cells to harmful stimuli. Here we studied effects of the KH-type splicing regulatory protein (KSRP), a RNA-binding protein, on innate immune response against H. pylori infection. We found that H. pylori infection downregulated KSRP expression directly, and that KSRP overexpression repressed upregulation of CXCL-2 expression induced by H. pylori and facilitated H. pylori proliferation in vitro. Similarly, KSRP overexpression in H. pylori mice also facilitated H. pylori proliferation and colonization, and induced more severe gastric mucosal damage. Intriguingly, CXCL-2 and HMOX-1 were upregulated in H. pylori infected mice after KSRP overexpression. This difference in expression of these genes implicated that KSRP was closely associated with and directly participated in the innate immune response against H. pylori. These results were beneficial for understanding the in vivo function of KSRP on innate immune response against pathogen infection.

Cryptosporidium parvum infection attenuates the ex vivo propagation of murine intestinal enteroids

Cryptosporidium, a ubiquitous coccidian protozoan parasite that infects the gastrointestinal epithelium and other mucosal surfaces, is an important opportunistic pathogen for immunocompromised individuals and a common cause of diarrhea in young children in the developing countries. One of the pathological hallmarks of intestinal cryptosporidiosis is villous atrophy, which results in a shorter height of intestinal villi. Here, we investigated the effects of Cryptosporidium infection on intestinal epithelial growth, using an ex vivo model of intestinal cryptosporidiosis employing enteroids from mice. We detected infection of enteroids isolated from immunocompetent adult and neonatal mice after ex vivo exposure to Cryptosporidium sporozoites. We observed a significant inhibition of enteroid propagation following infection. Intriguingly, we identified a decreased expression level of intestinal stem cell markers in enteroids following C. parvum infection. We further measured the expression levels of several Wnt antagonists or agonists in infected enteroids, as induction of the Wnt/β‐catenin activation is a key factor for intestinal stem cell function. We detected a markedly increased level of the Dickkopf‐related protein 1 and decreased level of the Wnt family member 5a in enteroids after infection. The low density lipoprotein receptor‐related protein 5, one of the Wnt co‐receptors, is downregulated in the infected enteroids. In addition, increased apoptotic cell death and cell senescence were observed in the infected enteroids. Our results demonstrate a significant inhibitory effect of Cryptosporidium infection on the ex vivo propagation of enteroids from mice, providing additional insights into the impact of Cryptosporidium infection on intestinal epithelial growth.

KSRP specifies monocytic and granulocytic differentiation through regulating miR-129 biogenesis and RUNX1 expression

RNA-binding proteins (RBPs) integrate the processing of RNAs into post-transcriptional gene regulation, but the direct contribution of them to myeloid cell specification is poorly understood. Here, we report the first global RBP transcriptomic analysis of myeloid differentiation by combining RNA-seq analysis with myeloid induction in CD34⁺ hematopoietic progenitor cells. The downregulated expression of the KH-Type Splicing Regulatory Protein (KSRP) during monocytopoiesis and up-regulated expression during granulopoiesis suggests that KSRP has divergent roles during monocytic and granulocytic differentiation. A further comparative analysis of miRNA transcripts reveals that KSRP promotes the biogenesis of miR-129, and the expression patterns and roles of miR-129 in myeloid differentiation are equivalent to those of KSRP. Finally, miR-129 directly blocks the expression of Runt Related Transcription Factor 1 (RUNX1), which evokes transcriptional modulation by RUNX1. Based on our findings, KSRP, miR-129, and RUNX1 participate in a regulatory axis to control the outcome of myeloid differentiation.

Cryptosporidium in humans and animals-a one health approach to prophylaxis

Cryptosporidium is a major cause of moderate-to-severe diarrhoea in humans worldwide, second only to rotavirus. Due to the wide host range and environmental persistence of this parasite, cryptosporidiosis can be zoonotic and associated with foodborne and waterborne outbreaks. Currently, 31 species are recognized as valid, and of these, Cryptosporidium hominis and Cryptosporidium parvum are responsible for the majority of infections in humans. The immune status of the host, both innate and adaptive immunity, has a major impact on the severity of the disease and its prognosis. Immunocompetent individuals typically experience self-limiting diarrhoea and transient gastroenteritis lasting up to 2 weeks and recover without treatment, suggesting an efficient host antiparasite immune response. Immunocompromised individuals can suffer from intractable diarrhoea, which can be fatal. Effective drug treatments and vaccines are not yet available. As a result of this, the close cooperation and interaction between veterinarians, health physicians, environmental managers and public health operators is essential to properly control this disease. This review focuses on a One Health approach to prophylaxis, including the importance of understanding transmission routes for zoonotic Cryptosporidium species, improved sanitation and better risk management, improved detection, diagnosis and treatment and the prospect of an effective anticryptosporidial vaccine.

KSRP suppresses cell invasion and metastasis through miR-23a-mediated EGR3 mRNA degradation in non-small cell lung cancer

KH-type splicing regulatory protein (KSRP) is a single-strand RNA binding protein which regulates mRNA stability either by binding to AU-rich elements (AREs) of mRNA 3'UTR or by facilitating miRNA biogenesis to target mRNA. Unlike its well-characterized function at the molecular level in maintaining RNA homeostasis, the role of KSRP in cancer progression remains largely unknown. Here we investigate the role of KSRP in non-small cell lung cancer (NSCLC). We first examined KSRP expression by immunohistochemistry in a cohort containing 196 NSCLC patients and observed a strong positive correlation between KSRP expression and survival of NSCLC patients. Multivariate analysis further identified KSRP as an independent prognostic factor. Manipulating KSRP expression significantly affected in vitro cell mobility and in vivo metastatic ability of NSCLC cells. Microarray analysis identified an ARE-containing gene, EGR3, as a downstream effector of KSRP in NSCLC. Interestingly, we found that KSRP decreased EGR3 mRNA stability in an ARE-independent manner. By screening KSRP-regulated miRNAs in NSCLC cells, we further found that miR-23a directly binds to EGR3 3'UTR, reducing EGR3 expression and thereby inhibiting NSCLC cell mobility. Our findings implicate a targetable KSRP/miR-23a/EGR3 signaling axis in advanced tumor phenotypes.

MicroRNAs: Roles in Regulating Neuroinflammation

MicroRNAs (miRNAs) are small noncoding RNAs that broadly affect cellular and physiological function in all multicellular organisms. Here, the role of miRNAs in neuroinflammation is considered. miRNAs are 21- to 23-oligonucleotide RNAs that regulate translation of specific RNAs by binding to complementary regulatory RNA sequences, thereby causing mRNA degradation or sequestration. More than 5000 miRNAs likely exist in humans, and each miRNA binds an average of 200 RNAs. Specific immunomodulatory miRNAs can regulate a set of RNAs in a coordinated manner, suggesting that effective miRNA-based therapeutic manipulations for neuroinflammatory conditions may be revealed. For instance, miRNAs that preferentially inhibit translation of many cellular anti-inflammatory proteins could drive a pro-inflammatory response. Key pro-inflammatory ( miR-155, miR-27b, miR-326), anti-inflammatory ( miR-124, miR-146a, miR-21, miR-223), and mixed immunomodulatory ( let-7 family) miRNAs regulate neuroinflammation in various pathologies, including spinal cord injury, multiple sclerosis, ischemic stroke, and Alzheimer's disease. miRNAs represent a newly revealed layer of physiological complexity, the therapeutic benefits of which remain to be fully explored and exploited. In this review, we discuss the role of miRNAs in neuroinflammatory regulation and discuss how controlling miRNAs could alter cellular machinery to improve neuroinflammatory dynamics.

KH-type splicing regulatory protein mediate inflammatory response in gastric epithelial cells induced by lipopolysaccharide

To study differential expressions of KH-type splicing regulatory protein (KSRP) and inflammatory factors and to explore the relationship between them in Lipopolysaccharide (LPS)-induced gastric epithelial cells (GES-1), cells were exposed to LPS for 24 h in the presence or absence of SC-514. Western blot and real-time PCR (RT-PCR) were used to analysis the contents of KSRP, inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2). The results showed that LPS decreased the expression of KSRP protein in GES-1 cells, but not KSRP mRNA, while increasing the levels of iNOS and COX-2 proteins and mRNAs in GES-1cells. High expression of KSRP induced low expressions and stabilities of iNOS and COX-2 in GES-1 cells, indicated that KSRP protein presented negative correlation with iNOS and COX-2 with LPS stimulation. In conclusion, the regulation of expression of KSRP was mainly achieved through post-translational modification. KSRP protein participated in regulating the expression of iNOS and COX-2 in their transcription and translation levels. In response to LPS or gram negative pathogenic microorganism, KSRP could regulate Toll-like receptor (TLR)/ Nuclear factor-kappa B (NF-κB) signal pathway in GES-1 cells.

Neonatal mucosal immunology

Although largely deprived from exogenous stimuli in utero, the mucosal barriers of the neonate after birth are bombarded by environmental, nutritional, and microbial exposures. The microbiome is established concurrently with the developing immune system. The nature and timing of discrete interactions between these two factors underpins the long-term immune characteristics of these organs, and can set an individual on a trajectory towards or away from disease. Microbial exposures in the gastrointestinal and respiratory tracts are some of the key determinants of the overall immune tone at these mucosal barriers and represent a leading target for future intervention strategies. In this review, we discuss immune maturation in the gut and lung and how microbes have a central role in this process.

The contribution of toll-like receptor 2 on Helicobacter pylori activation of the nuclear factor-kappa B signaling pathway in gastric epithelial cells

Helicobacter pylori (H. pylori) is a spiral shaped gram-negative bacterium that induces immune responses in the gastric mucosa. Toll-like receptors (TLRs) play important roles in mediating inflammatory cytokines by recognition of conserved molecular patterns on bacteria. Changes in the expression of toll-like receptor (TLR) 2, TLR4 and the relative inflammatory cytokines were analyzed in normal gastric epithelial GES-1 cells following treatment with H. pylori or Escherichia coli lipopolysaccharide (E. coli LPS) in order to investigate the contribution of TLRs in recognizing and mediating the inflammatory response to H. pylori, and study the differences in TLRs' performance between H. pylori and E. coli. Specific inhibitors for the declines in TLR2 and TLR4 were also employed. The results showed that H. pylori infection increased TLR2 expression in GES-1 cells, but TLR4 remained unchanged regardless of H. pylori or TLR2 small interfering RNA treatment. Furthermore, the secretion of cyclooxygenase-2 (COX-2) induced by H. pylori was inhibited by declines in TLR2, but not in TLR4. In conclusion, TLR2 plays an even more important role than TLR4 not only in recognizing H. pylori, but also in the induction of inflammatory cytokines initiated by H. pylori. However, both TLR2 and TLR4 are necessary in mediating the inflammatory response to E. coli LPS.