SMETASeq: Combined Profiling of Microbiota and Host Small RNAs.
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ABSTRACT:
SUBMITTER: Mjelle R
PROVIDER: S-EPMC7229328 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Viruses are obligatory intracellular parasites that require the host machinery to replicate. During their replication cycle, viral RNA intermediates can be recognized and degraded by different antiviral mechanisms that include RNA decay, RNA interference, and RNase L pathways. As a consequence of viral RNA degradation, infected cells can accumulate virus-derived small RNAs at high levels compared to cellular molecules. These small RNAs are imprinted with molecular characteristics that reflect their origin. First, small RNAs can be used to reconstruct viral sequences and identify the virus from which they originated. Second, other molecular features of small RNAs such as size, polarity, and base preferences depend on the type of viral substrate and host mechanism of degradation. Thus, the pattern of small RNAs generated in infected cells can be used as a molecular footprint to identify and characterize viruses independent on sequence homology searches against known references. Hence, sequencing of small RNAs obtained from infected cells enables virus discovery and characterization using both sequence-dependent strategies and novel pattern-based approaches. Recent studies are helping unlock the full application of small RNA sequencing for virus discovery and characterization. WIREs RNA 2016, 7:824-837. doi: 10.1002/wrna.1361 For further resources related to this article, please visit the WIREs website.
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Project description:BackgroundmicroRNAs (miRNAs), a class of short, non-coding RNA can be found in a highly stable, cell-free form in mammalian body fluids. Specific miRNAs are secreted by parasitic nematodes in exosomes and have been detected in the serum of murine and dog hosts infected with the filarial nematodes Litomosoides sigmodontis and Dirofilaria immitis, respectively. Here we identify extracellular, parasite-derived small RNAs associated with Onchocerca species infecting cattle and humans.MethodsSmall RNA libraries were prepared from total RNA extracted from the nodule fluid of cattle infected with Onchocerca ochengi as well as serum and plasma from humans infected with Onchocerca volvulus in Cameroon and Ghana. Parasite-derived miRNAs were identified based on the criteria that sequences unambiguously map to hairpin structures in Onchocerca genomes, do not align to the human genome and are not present in European control serum.ResultsA total of 62 mature miRNAs from 52 distinct pre-miRNA candidates were identified in nodule fluid from cattle infected with O. ochengi of which 59 are identical in the genome of the human parasite O. volvulus. Six of the extracellular miRNAs were also identified in sequencing analyses of serum and plasma from humans infected with O. volvulus. Based on sequencing analysis the abundance levels of the parasite miRNAs in serum or plasma range from 5 to 127 reads/per million total host miRNA reads identified, comparable to our previous analyses of Schistosoma mansoni and L. sigmodontis miRNAs in serum. All six of the O. volvulus miRNAs identified have orthologs in other filarial nematodes and four were identified in the serum of mice infected with L. sigmodontis.ConclusionsWe have identified parasite-derived miRNAs associated with onchocerciasis in cattle and humans. Our results confirm the conserved nature of RNA secretion by diverse nematodes. Additional species-specific small RNAs from O. volvulus may be present in serum based on the novel miRNA sequences identified in the nodule fluid. In our analyses comparison to European control serum illuminates the scope for false-positives, warranting caution in criteria that should be applied to identification of biomarkers of infection.
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Project description:Growing evidence suggests the importance of the small intestinal bacteria in the diet-host-microbiota dialogue in various facets of health and disease. Yet, this body site is still poorly explored and its ecology and mechanisms of interaction with the host are just starting to be unraveled. In this review, we describe the current knowledge on the small intestinal ecology, its composition and diversity, and how the intestinal bacteria in homeostatic conditions participate in nutrient digestion and absorption. We illustrate the importance of a controlled bacterial density and of the preservation of absorptive surface for the host's nutritional status. In particular, we discuss these aspects of the small intestinal environment in the framework of two disease conditions, namely small intestinal bacterial overgrowth (SIBO) and short bowel syndrome (SBS). We also detail in vivo, ex vivo and in vitro models developed to simulate the small intestinal environment, some applied for (diet-)host-bacteria interaction studies. Lastly, we highlight recent technological, medical and scientific advances applicable to investigate this complex and yet understudied body environment to broaden our knowledge in support of further progress in the medical practice, and to proceed towards the integration of the (small)intestinal bacteria in personalized therapeutic approaches.
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