Ruminiclostridium 5, Parabacteroides distasonis, and bile acid profile are modulated by prebiotic diet and associate with facilitated sleep/clock realignment after chronic disruption of rhythms.

Chronic disruption of rhythms (CDR) impacts sleep and can result in circadian misalignment of physiological systems which, in turn, is associated with increased disease risk. Exposure to repeated or severe stressors also disturbs sleep and diurnal rhythms. Prebiotic nutrients produce favorable changes in gut microbial ecology, the gut metabolome, and reduce several negative impacts of acute severe stressor exposure, including disturbed sleep, core body temperature rhythmicity, and gut microbial dysbiosis. In light of previous compelling evidence that prebiotic diet broadly reduces negative impacts of acute, severe stressors, we hypothesize that prebiotic diet will also effectively mitigate the negative impacts of chronic disruption of circadian rhythms on physiology and sleep/wake behavior. Male, Sprague Dawley rats were fed diets enriched in prebiotic substrates or calorically matched control chow. After 5 weeks on diet, rats were exposed to CDR (12 h light/dark reversal, weekly for 8 weeks) or remained on undisturbed normal light/dark cycles (NLD). Sleep EEG, core body temperature, and locomotor activity were recorded via biotelemetry in freely moving rats. Fecal samples were collected on experimental days -33, 0 (day of onset of CDR), and 42. Taxonomic identification and relative abundances of gut microbes were measured in fecal samples using 16S rRNA gene sequencing and shotgun metagenomics. Fecal primary, bacterially modified secondary, and conjugated bile acids were measured using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Prebiotic diet produced rapid and stable increases in the relative abundances of Parabacteroides distasonis and Ruminiclostridium 5. Shotgun metagenomics analyses confirmed reliable increases in relative abundances of Parabacteroides distasonis and Clostridium leptum, a member of the Ruminiclostridium genus. Prebiotic diet also modified fecal bile acid profiles; and based on correlational and step-wise regression analyses, Parabacteroides distasonis and Ruminiclostridium 5 were positively associated with each other and negatively associated with secondary and conjugated bile acids. Prebiotic diet, but not CDR, impacted beta diversity. Measures of alpha diversity evenness were decreased by CDR and prebiotic diet prevented that effect. Rats exposed to CDR while eating prebiotic, compared to control diet, more quickly realigned NREM sleep and core body temperature (ClockLab) diurnal rhythms to the altered light/dark cycle. Finally, both cholic acid and Ruminiclostridium 5 prior to CDR were associated with time to realign CBT rhythms to the new light/dark cycle after CDR; whereas both Ruminiclostridium 5 and taurocholic acid prior to CDR were associated with NREM sleep recovery after CDR. These results support our hypothesis and suggest that ingestion of prebiotic substrates is an effective strategy to increase the relative abundance of health promoting microbes, alter the fecal bile acid profile, and facilitate the recovery and realignment of sleep and diurnal rhythms after circadian disruption.

CORP: Assessing author compliance with data presentation guidelines for manuscript figures.

The present study was undertaken to address the concern that author compliance with American Physiological Society (APS) journal instructions to authors for data presentation in manuscript figures is inadequate. Common instances of noncompliance are omitted molecular weight markers for immunoblots and bar graphs lacking individual data points. The American Journal of Physiology-Heart and Circulatory Physiology (AJP-Heart and Circ) editorial team designed a program to assess figure data presentation in submitted manuscripts. The intended outcome was to improve author compliance with APS data presentation guidelines and to improve overall rigor and reproducibility in articles published in AJP-Heart and Circ. The AJP-Heart and Circ team invited 37 peer reviewers to participate in a figure reviewer project (FRp). Over a period of five months, 32 first-revision manuscripts were enrolled in the FRp. Each manuscript was reviewed by the original peer reviewers and an additional figure reviewer (FR). Post-peer review, corresponding authors and FRs were surveyed for insight into their experiences. Of the 32 corresponding authors invited, 20 (63%) responded to the survey. In response to the survey, 100% of respondents stated that peer review was performed in a timely fashion despite the additional FR. When asked whether the FR experience had any effect on how one would present data in manuscript figures in future submissions, 65% of authors and 83% of FRs said yes. In addition, 63% of authors responding agreed that the overall quality of their figures was improved after revising based on FR comments. This exercise resulted in improved compliance with APS data presentation guidelines and changed attitudes among both authors and reviewers as to the need for consistent and clear data presentation in manuscript figures.NEW & NOTEWORTHY The goal of the American Journal of Physiology-Heart and Circulatory Physiology figure reviewer program was to improve author compliance with existing APS data presentation instructions for manuscript figures. The result was an improvement in compliance with these guidelines. Time from submission to final decision did not significantly increase for papers with the additional figure reviewer, and both figure reviewers and corresponding authors reported positive feedback in post-program surveys.

Feeding the developing brain: Juvenile rats fed diet rich in prebiotics and bioactive milk fractions exhibit reduced anxiety-related behavior and modified gene expression in emotion circuits.

Early life nutrition is critical for brain development. Dietary prebiotics and bioactive milk fractions support brain development by increasing plasticity and altering activity in brain regions important for cognition and emotion regulation, perhaps through the gut-microbiome-brain axis. Here we examined the impact of a diet containing prebiotics, lactoferrin, and milk fat globule membrane (test diet) on beneficial gut bacteria, basal gene expression for activity and plasticity markers within brain circuits important for cognition and anxiety, and anxiety-related behavior in the open field. Juvenile male F344 rats were fed the test diet or a calorically matched control diet beginning postnatal day 24. After 4 weeks on diets, rats were sacrificed and brains were removed. Test diet significantly increased mRNA expression for cfos, brain derived neurotropic factor, and the GluN1 subunit of the NMDA receptor in the prefrontal cortex and reduced cfos mRNA within the amygdala. Diet-induced increases in fecal Lactobacillus spp., measured using selective bacterial culture, positively correlated with altered gene expression for cfos and serotonin receptors within multiple brain regions. In a separate cohort of juvenile rats, 4 weeks of the test diet increased time spent in the center of the open field, a behavior indicative of reduced anxiety. These data demonstrate that early life diets containing prebiotics and bioactive milk fractions can adaptively alter genes in neural circuits underlying emotion regulation and impact anxiety-related behavior.

Cyclosporine A induced epithelial-mesenchymal transition in human renal proximal tubular epithelial cells.

BACKGROUND: Tubulointerstitial fibrosis is a relatively common and sinister complication of cyclosporine A (CsA) therapy that limits its clinical use. CsA may have direct effects on renal tubular epithelial cells by promoting epithelial-mesenchymal transition (EMT). EMT plays an important role in embryonic development and tumourigenesis and has been described in organ remodelling during fibrogenesis. In this study, we investigated the effects of CsA on a human renal cell line as a model system to test the hypothesis that CsA can induce renal EMT. METHODS: Human renal proximal tubular cells were treated with CsA (0.42-42 microm) for periods up to 72 h. Viability was assessed by the Alamar Blue assay. Morphological changes were assessed by phase contrast microscopy. The effects on epithelial adherens molecule, beta-catenin and stress fibre protein, F-actin were analysed by indirect immunofluorescence. Reverse transcription--polymerse chain reaction was performed to measure the mRNA levels of extracellular matrix components. Expression of transforming growth factor-beta was measured by western blotting. Expression and activity of matrix metalloproteinases were measured by gelatin zymography. RESULTS: CsA induced striking morphological changes in epithelial cells, including changes in cellular morphology, F-actin stress fibre formation, delocalization of the adherens junction protein beta-catenin and increased levels of collagen IV and fibronectin. In addition, CsA-induced EMT was associated with increased TGF-beta1 protein levels and EMT was markedly attenuated in the presence of anti-TGF-beta1 antibody. CsA-induced EMT was also associated with increased expression of connective tissue growth factor (CTGF) suggesting that this molecule may serve as downstream mediator of TGF-beta1 pro-fibrotic activity in this setting. CONCLUSIONS: In aggregate, these data suggest that CsA is a direct stimulus for EMT in renal tubule epithelial cells and implicate TGF-beta1 and CTGF as mediators of this response. The further delineation of the molecular components of this pro-fibrogenic response may suggest novel strategies through which to prevent CsA-induced tubulo-interstitial fibrosis in vivo.