ObjectiveThe initial colonisation of the human microbiota and the impact of maternal health on neonatal microbiota at birth remain largely unknown. The aim of our study is to investigate the possible dysbiosis of maternal and neonatal microbiota associated with gestational diabetes mellitus (GDM) and to estimate the potential risks of the microbial shift to neonates.DesignPregnant women and neonates suffering from GDM were enrolled and 581 maternal (oral, intestinal and vaginal) and 248 neonatal (oral, pharyngeal, meconium and amniotic fluid) samples were collected. To avoid vaginal bacteria contaminations, the included neonates were predominantly delivered by C-section, with their samples collected within seconds of delivery.ResultsNumerous and diverse bacterial taxa were identified from the neonatal samples, and the samples from different neonatal body sites were grouped into distinct clusters. The microbiota of pregnant women and neonates was remarkably altered in GDM, with a strong correlation between certain discriminatory bacteria and the oral glucose tolerance test. Microbes varying by the same trend across the maternal and neonatal microbiota were observed, revealing the intergenerational concordance of microbial variation associated with GDM. Furthermore, lower evenness but more depletion of KEGG orthologues and higher abundance of some viruses (eg, herpesvirus and mastadenovirus) were observed in the meconium microbiota of neonates associated with GDM.ConclusionGDM can alter the microbiota of both pregnant women and neonates at birth, which sheds light on another form of inheritance and highlights the importance of understanding the formation of early-life microbiome.

tRNA-derived small RNA (tsRNA) is a novel regulatory small non-coding RNA and participates in diverse physiological and pathological processes. However, the presence of tsRNAs in exosome and their diagnostic potential remain unclear. In this study, we took advantage of small RNA-seq technology to profile exosomal tsRNAs from cell culture medium and plasma, and found ubiquitous presence of tsRNAs in exosome. To explore the potential value of tsRNA for cancer diagnosis, we compared exosomal tsRNA levels between liver cancer patients and healthy donors, revealing that tsRNAs were dramatically increased in plasma exosomes of liver cancer patients. Importantly, patients with liver cancer exhibited significantly higher levels of four tsRNAs (tRNA-ValTAC-3, tRNA-GlyTCC-5, tRNA-ValAAC-5 and tRNA-GluCTC-5) in plasma exosome, demonstrating that plasma exosomal tsRNA could serve as a novel diagnostic biomarker. Taken together, our results not only expand non-coding RNA species in exosome, but also highlight the potential of tsRNAs as a promising biomarker for cancer diagnosis. Electronic supplementary material The online version of this article (10.1186/s12943-019-1000-8) contains supplementary material, which is available to authorized users.

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Phenotypic flexibility of various morphological and physiological characters is widespread in animals. Resident endothermic animals of temperate climates provide a natural experiment in phenotypic flexibility. In this study, we took an integrative approach to assess seasonal and geographic influences on metabolism in Eurasian tree sparrows (Passer montanus). We measured resting metabolic rate (RMR), masses of internal organs, mitochondrial respiration capacities in liver and muscle, cytochrome C oxidase (COX) activities in liver and muscle, and circulating levels of plasma triiodothyronine (T3) and thyroxine (T4) in summer and winter sparrows at two sites from southeastern (Wenzhou) and northeastern (Qiqihar) China that differ in climate. Body masses of tree sparrows were significantly higher in winter than in summer at both sites but did not differ with latitude. RMRs of tree sparrows varied significantly with both latitude and season, with RMRs of Qiqihar birds being higher than those of Wenzhou birds and with RMRs being higher in winter than in summer. Consistently, dry masses of brain, lung, liver, gizzard, small intestine, rectum, and total digestive tract varied significantly with either latitude or season. State 4 respiration and COX activity in liver and muscle were remarkably higher in Qiqihar and increased significantly in winter. Circulating levels of plasma T3 also showed significant seasonal and latitudinal variation and was higher in Qiqihar in winter than in other groups. These data suggest that tree sparrows mainly coped with cold by enhancing thermogenic capacities through heightened activity of respiratory enzymes and higher levels of plasma thyroid hormones (T3). These results are consistent with a pronounced seasonal and latitudinal phenotypic flexibility mediated through physiological and biochemical adjustments in Eurasian tree sparrows.

Inflammatory bowel disease (IBD) is characterized by chronic relapsing inflammatory disorders of the gastrointestinal tract, and includes two major phenotypes: ulcerative colitis and Crohn's disease. The pathogenesis of IBD is not fully understood as of yet. It is believed that IBD results from complicated interactions between environmental factors, genetic predisposition, and immune disorders. miRNAs are a class of small non-coding RNAs that can regulate gene expression by targeting the 3′-untranslated region of specific mRNAs for degradation or translational inhibition. miRNAs are considered to play crucial regulatory roles in many biologic processes, such as immune cellular differentiation, proliferation, and apoptosis, and maintenance of immune homeostasis. Recently, aberrant expression of miRNAs was revealed to play an important role in autoimmune diseases, including IBD. In this review, we discuss the current understanding of how miRNAs regulate autoimmunity and inflammation by affecting the differentiation, maturation, and function of various immune cells. In particular, we focus on describing specific miRNA expression profiles in tissues and peripheral blood that may be associated with the pathogenesis of IBD. In addition, we summarize the opportunities for utilizing miRNAs as new biomarkers and as potential therapeutic targets in IBD.