A glutamatergic network mediates lithium response in bipolar disorder as defined by epigenome pathway analysis
PHARMACOGENOMICS
Authors: Higgins, Gerald A.; Allyn-Feuer, Ari; Barbour, Edward; Athey, Brian D.
Abstract
Aim: A regulatory network in the human brain mediating lithium response in bipolar patients was revealed by analysis of functional SNPs from genome-wide association studies (GWAS) and published gene association studies, followed by epigenome mapping. Methods: An initial set of 23,312 SNPs in linkage disequilibrium with lead SNPs, and sub-threshold GWAS SNPs rescued by pathway analysis, were studied in the same populations. These were assessed using our workflow and annotation by the epigenome roadmap consortium. Results: Twenty-seven percent of 802 SNPs that were associated with lithium response (13 published studies gene association studies and two GWAS) were shared in common with 1281 SNPs from 18 GWAS examining psychiatric disorders and adverse events associated with lithium treatment.Nineteen SNPs were annotated as active regulatory elements such as enhancers and promoters in a tissue-specific manner. They were located within noncoding regions of ten genes: ANK3, ARNTL, CACNA1C, CACNG2, CDKN1A, CREB1, GRIA2, GSK3B, NR1D1 and SLC1A2. Following gene set enrichment and pathway analysis, these genes were found to be significantly associated (p = 10(-27); Fisher exact test) with an AMPA2 glutamate receptor network in human brain. Our workflow results showed concordance with annotation of regulatory elements from the epigenome roadmap. Analysis of cognate mRNA and enhancer RNA exhibited patterns consistent with an integrated pathway in humanbrain. Conclusion: This pharmacoepigenomic regulatory pathway is located in the same brain regions that exhibit tissue volume loss in bipolar disorder. Although in silico analysis requires biological validation, the approach provides value for identification of candidatevariants that may be used in pharmacogenomic testing to identify bipolar patients likely to respond to lithium.
Modulation by adiponectin of circadian clock rhythmicity in model mice for metabolic syndrome
ENDOCRINE JOURNAL
Authors: Hashinaga, Toshihiko; Wada, Nobuhiko; Otabe, Shuichi; Yuan, Xiaohong; Kurita, Yayoi; Kakino, Satomi; Tanaka, Kayo; Sato, Takahiro; Kojima, Masayasu; Ohki, Tsuyoshi; Nakayama, Hitomi; Egashira, Tomoka; Tajiri, Yuji; Yamada, Kentaro
Abstract
To assess the effect of adiponectin on the circadian rhythm disturbances associated with metabolic syndrome, we generated a KK/Ta mouse line expressing the human adiponectin transgene in the liver. Locomotor activity of control C57BL/6 mice was highest during the beginning of the dark period and low during the light period. Under constant darkness, the length of locomotor activity rhythm of control mice was slightly shorter than 24 h. In KK/Ta mice the peak of locomotor activity was blunted and significant activity was observed during the light period. Furthermore, KK/Ta mice showed shorter average period length of free-running locomotor activity rhythm when compared with control mice. However, the transgenic expression of adiponectin in the liver significantly altered the circadian rhythm of locomotor activity and the length of free-running rhythm of KK/Ta mice towards those of C57BL/6 mice. In the liver and skeletal muscles from control mice, mRNA levels of Arntl and Cry1 were increased during the dark period, whereas those of Dbp, Cry2, Per1 and Per2 were elevated during the light period. KK/Ta mice exhibited phase advances in circadian rhythms of Arntl, Dbp, Cry2 and Per2 in both tissues. The phase shifts of the circadian clock gene expression in the liver were attenuated in adiponectin-transgenic mice. These results suggest that adiponectin is a peripheral regulator of the circadian clocks in the brain and peripheral organs, and may be a novel target for the treatment of obesity-associated disorders of circadian rhythms.