The present study shows that the diurnal effect dominates the transcriptome of the human GS-1101 adipose tissue, with more than 25% of the transcribed genes being diurnally regu lated. This finding is consistent with observed circadian regulation in adipose in animal models, in which up to 50% of the genes are under circadian control. Moreover, the results demonstrated robust regulation of the core clock gene PER1 and of genes encoding for ribos ome processing and biogenesis and inflammatory proc esses. Ribosome biogenesis genes were on the diurnal incline, with levels rising by afternoon and remaining constant until evening. Ribosome biogenesis is an indica tor of cellular activity and, in this case, most likely driven by the AKT/PI3K/mTOR pathway.

A number of genes encode enzymes in glucose, mannose and fructose metab olism, with high expression levels in the morning and a decline in the afternoon through the evening, following the trend of PER1. Con versely, fuel accumulation genes, such as those involved in cholesterol biosynthesis, LDL receptor, and glucose transport have low levels in the morning and rise in the afternoon. Interestingly, there was no observed correla tion between the more typical lipogenesis or transporter genes, such as fatty acid synthase or GLUTs 2 and 4, and PER1 expression. These genes may be regulated in a more acute fashion by external stimulation, such as insulin or cholesterol, or may not be sensitive to diurnal regulation in the adipose tissue of mildly obese subjects. Many genes encoding for cytokines and other inflamma tion related proteins were also diurnally regulated.

The mRNA levels of this set of genes were inversely correlated with PER1 expression, with expression levels increasing dramatically from the morning through the afternoon and being highest in the evening. These genes had among the highest amplitudes of change, from 2 fold to 20 fold. Whereas studies have previously shown that inflammation related proteins, such as PAI 1, IL 6 and TNF, were diurnally regulated, the present result adds several new cytokines, including PTX3, IL1, IL10, GRO1, GRO2, CCL6, TGFA and CCL7 to the set of known diurnally regulated genes. Many cytokines, such as IL 6 and IL 8 and MCP 1, have been implicated in cardio vascular risk. the present study demonstrated that both IL 6 and IL 8 were significantly, but inversely, correlated with PER1. The observed associations between these pro inflammatory genes with the diurnal rhythm warrant fur ther investigation. To further characterize the physiology of the diurnal change in the human adipose, an unbiased in silico search for compound signatures common with the diurnally reg ulated genes in our study was performed using the pub licly Dacomitinib available Connectivity Nilotinib Sigma Map database.