Project description:The study was designed in order to identify genes differentially expressed when glucocorticoid signaling is blocked by a glucocorticoid-receptor antagonist (RU486 â?? mifepristone) in the context of brain inflammation induced by bacterial lipopolysaccharide (LPS). LPS is only able to cause murine brain damage in our experimental conditions upon RU486 pre-treatment. Hence, the study may reveal potential candidate genes to mediate neuroprotection or neurotoxicity. Due to the factorial design of the experiment, RU486 main-effect could be dissociated from the effects resultant of RU486/inflammation interaction. In addition, brain dissection was conducted to verify the effects in the brain side ipsilateral or contralateral to the site of intracerebral LPS infusion. Experiment Overall Design: C57Bl/6 mice received an i.p. injection of vehicle (DMSO - 50 microliters) or RU486 (50 mg/kg) and were submitted to surgery 4 h later. The mice receiving intraparenchymal injections were anesthetized and the right caudate putamen was reached, using a small cannula at the coordinates 0.0 mm anteroposterior, -2.0 mm lateral, and -3.0 mm dorsoventral according to a mouse brain atlas. The animals received an infusion of sterile pyrogen-free saline (1 microliter) or LPS (from Eschericia coli; serotype O55:B5; Sigma L2880 - 2.5 micrograms) over 2 min by means of a microinjection 18 pump. Animals were killed 12 h after the intracerebral infusion. The mice were anesthetized under isofluorane and blood was drawn via cardiac puncture before head decapitation. Brains were removed rapidly from the skulls and placed in cold phosphate buffered saline (PBS) solution. A brain region limited at plane anteroposterior +1.5 to -1.5 and dorsoventral -4.0 was dissected, separated in ipsilateral side and quickly immersed in liquid nitrogen. The tissue was stored at -80 oC until RNA extraction was performed. A total of 37 chips (MOE430A â?? Affymetrix, Santa Clara, CA) were used for oligonucleotide array analysis [one chip per biological sample; 8 groups (contralateral dmso/saline, dmso/LPS, RU486/saline, RU486/LPS and ipsilateral dmso/saline, dmso/LPS, RU486/saline, RU486/LPS) with 4 â?? 6 biological replicates each]. Expression values from the CEL files generated from scanning were obtained using RMA algorithm, available at http://www.bioconductor.org. The expression values were also inspected with GeneSpring software (Silicon Genetics). Statistical analysis was performed considering a factorial linear model according to the methods implemented in Limma package (R project packages are available at http://www.cran.r-project.org).

Project description:A multi-omic approach in a clinical experimental study identified circulating biomarkers reflecting glucocorticoid exposure. Background: Endogenous glucocorticoids (GC) are mechanistically linked to common diseases and are important as drugs in the treatment of many disorders. There is no marker that can measure and quantify GC action. Our aim was to identify circulating biomarkers of GC action using a clinical experimental study. Methods: In a randomized, crossover, single-blind trial, subjects with primary adrenal insufficiency received intravenous hydrocortisone infusion in a circadian pattern (physiological GC exposure) or isotonic saline (GC withdrawal) over 22 hours. Samples were collected at 7 AM (end of infusion). Integrated multi-omic analysis was used because of the complexity in GC action and the low number of subjects. The transcriptome in peripheral blood mononuclear cells (PBMCs) and adipose tissue, plasma miRNAomic, and serum metabolomics were compared between the interventions. Replication of the plasma miRNA findings was performed in three independent studies. Results: During GC withdrawal, overnight urinary cortisol and cortisone excretion were undetectable. Correlation and hypernetwork analyses identified a transcriptomic profile derived from PBMCs and adipose tissue predictive of GC exposure, and a multi-omic cluster predictive of GC exposure. From the circulating ‘omic data, decreased expression of plasma miR-122-5p was associated with increased GC exposure. This finding was reproduced in three independent studies. Conclusion: We developed a human experimental model for physiological GC exposure and withdrawal. The integrated multi-omic data identified circulating miRNAs and metabolites associated with GC-responsive genes. In independent studies, miR-122-5p was shown to be associated with GC exposure. Background: Endogenous glucocorticoids (GC) are mechanistically linked to common diseases and are important as drugs in the treatment of many disorders. There is no marker that can measure and quantify GC action. Our aim was to identify circulating biomarkers of GC action using a clinical experimental study.

Dataset Information

Brief Hydrocortisone Infusion Differentially Influences Blood Leukocyte and Monocyte Gene Expression Before and After Endotoxin Administration in Humans (supported by NIH grant GM34695)

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