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

Neospora caninum infection specifically suppresses the expression of a host lncRNA XR_001919077.1 to facilitate parasite propagation by modulating host cell mitochondrial function and autophagy

Neospora caninum is one of the most common pathogens causing reproductive failure in ruminants (e.g., cattle and goats) worldwide. However, due to a poor understanding of the pathogenic mechanisms of N. caninum infection, no effective drugs and vaccines are currently available. Long non-coding RNAs (lncRNAs) have been reported to be important regulators involved in a great number of physiological and pathological processes. Our previous study found that N. caninum infection induced significantly aberrant expression of lncRNA profiles in caprine endometrial epithelial cells (EECs). In the present study, we found that N. caninum infection specifically suppressed the expression of a novel lncRNA, XR_001919077.1, and knockdown of XR_001919077.1 with small interfering RNA significantly promoted the propagation of N. caninum in caprine EECs. Rapid amplification of cDNA ends analysis generated six splice variants of XR_001919077.1, with lengths ranging from 592 to 694 nt. Transfection of the full length of each variant markedly inhibited the propagation of N. caninum in caprine EECs. Further study suggested that XR_001919077.1 acted as a sponge of Chi-miR-93-5p to promote the expression of sirt1, and the XR_001919077.1/Chi-miR-93-5p/sirt1 axis significantly delayed the in vitro growth of N. caninum in caprine EECs by regulating host cell mitochondrial function and autophagy. Our findings provide a novel insight to understand the interactions between N. caninum and host cells.IMPORTANCEThe uterus is an indispensable reproductive organ for embryo implantation and fetal growth. The endometrium is more vulnerable to infection by pathogenic microorganisms resulting in an increased risk of miscarriage. Neospora caninum is one of the most common pathogens causing miscarriage in ruminants and is able to naturally inhabit the uterus, with N. caninum tissue cysts found in the endometrium. Recent advances in N. caninum research have revealed aberrant expression of long non-coding RNA (lncRNA) profiles in infected caprine endometrial epithelial cells. In the present study, N. caninum, but not Toxoplasma gondii, which has similar morphological and biological features to N. caninum, specifically suppresses the expression of a host lncRNA, XR_ 001919077.1, to impair host's defense through the competitive endogenous RNA mechanism to modulate the host cell mitochondrial function and autophagy to facilitate parasite propagation. The findings suggest a novel immune evasion strategy of N. caninum to facilitate intracellular propagation and provide an alternative path to develop control strategies against neosporosis.

Metaviromic reveals the dynamics and diversity of the virosphere in wastewater samples from Natal, Brazil

The COVID-19 pandemic underscored the significance of omics technology and Wastewater-Based Epidemiology for epidemic preparedness. This study investigates the virosphere in wastewater samples from Natal (Brazil), aiming to understand its structure, relationships, and potential. Metaviromic analysis was used on DNA and RNA from weekly samples collected over a year (June/2021 to May/2022) from three wastewater treatment plants. The virosphere showed stability, particularly in viruses infecting microorganisms and plants. However, an alternation of representatives of viruses that infect animals has been observed. Among the most abundant viruses infecting microorganisms are genera associated with the bacterial genera Escherichia, Pseudomonas, and Caulobacte. Regarding the viruses infecting plants, Sobemovirus and Tobamovirus are the most abundant genera. Odontoglossum ringspot virus was identified as a possible RNA virus biomarker. Among DNA viruses infecting animals, genera Bocaparvovirus and Mastadenovirus are the most prevalent. Intriguingly, some Poxviridae family members were observed in the samples. Co-occurrence network analysis identified potential biomarkers like Volepox virus, Anatid herpesvirus 1, and Caviid herpesvirus 2. Among RNA viruses affecting animals, Mamastrovirus, Rotavirus, and Norovirus genera were the most abundant pathogens. Furthermore, members of the Coronaviridae family exhibited a high degree of centrality values in the co-occurrence network, even connecting with unclassified viruses. The study emphasizes the importance of research in understanding the roles of unclassified viruses. In addition, we observed an association between Coronaviridae reads, rainfall, and the number of reported COVID-19 cases. Our study highlights the diversity and complexity of the viral community in wastewater and the need for research to understand better the ecological roles unclassified viruses play. Such advances will significantly contribute to our preparedness and response to future viral threats. Furthermore, our study contributes to knowledge of virosphere dynamics, offering insights that can contribute to the direction of future public health policies and interventions.

Noncanonical microprotein regulation of immunity

The immune system is highly regulated but, when dysregulated, suboptimal protective or overly robust immune responses can lead to immune-mediated disorders. The genetic and molecular mechanisms of immune regulation are incompletely understood, impeding the development of more precise diagnostics and therapeutics for immune-mediated disorders. Recently, thousands of previously unrecognized noncanonical microprotein genes encoded by small open reading frames have been identified. Many of these microproteins perform critical functions, often in a cell- and context-specific manner. Several microproteins are now known to regulate immunity; however, the vast majority are uncharacterized. Therefore, illuminating what is often referred to as the "dark proteome," may present opportunities to tune immune responses more precisely. Here, we review noncanonical microprotein biology, highlight recently discovered examples regulating immunity, and discuss the potential and challenges of modulating dysregulated immune responses by targeting microproteins.

Cryptosporidium Genomics - Current Understanding, Advances, and Applications

Purpose of Review

Here we highlight the significant contribution that genomics-based approaches have had on the field of Cryptosporidium research and the insights these approaches have generated into Cryptosporidium biology and transmission.

Recent Findings

There are advances in genomics, genetic manipulation, gene expression, and single-cell technologies. New and better genome sequences have revealed variable sub-telomeric gene families and genes under selection. RNA expression data now include single-cell and post-infection time points. These data have provided insights into the Cryptosporidium life cycle and host-pathogen interactions. Antisense and ncRNA transcripts are abundant. The critical role of the dsRNA virus is becoming apparent.

Summary

The community's ability to identify genomic targets in the abundant, yet still lacking, collection of genomic data, combined with their increased ability to assess function via gene knock-out, is revolutionizing the field. Advances in the detection of virulence genes, surveillance, population genomics, recombination studies, and epigenetics are upon us.

Cryptosporidium parvum infection alters the intestinal mucosa transcriptome in neonatal calves: implications for immune function

One of the leading causes of infectious diarrhea in newborn calves is the apicomplexan protozoan Cryptosporidium parvum (C. parvum). However, little is known about its immunopathogenesis. Using next generation sequencing, this study investigated the immune transcriptional response to C. parvum infection in neonatal calves. Neonatal male Holstein-Friesian calves were either orally infected (N = 5) or not (CTRL group, N = 5) with C. parvum oocysts (gp60 subtype IIaA15G2R1) at day 1 of life and slaughtered on day 7 after infection. Total RNA was extracted from the jejunal mucosa for short read. Differentially expressed genes (DEGs) between infected and CTRL groups were assessed using DESeq2 at a false discovery rate < 0.05. Infection did not affect plasma immunohematological parameters, including neutrophil, lymphocyte, monocyte, leucocyte, thrombocyte, and erythrocyte counts as well as hematocrit and hemoglobin concentration on day 7 post infection. The immune-related DEGs were selected according to the UniProt immune system process database and were used for gene ontology (GO) and pathway enrichment analysis using Cytoscape (v3.9.1). Based on GO analysis, DEGs annotated to mucosal immunity, recognizing and presenting antigens, chemotaxis of neutrophils, eosinophils, natural killer cells, B and T cells mediated by signaling pathways including toll like receptors, interleukins, tumor necrosis factor, T cell receptor, and NF-KB were upregulated, while markers of macrophages chemotaxis and cytosolic pattern recognition were downregulated. This study provides a holistic snapshot of immune-related pathways induced by C. parvum in calves, including novel and detailed feedback and feedforward regulatory mechanisms establishing the crosstalk between innate and adaptive immune response in neonate calves, which could be utilized further to develop new therapeutic strategies.