Evidence for association of bipolar disorder to haplotypes in the 22q12.3 region near the genes stargazin, IFT27 and parvalbumin.

We have previously reported genome-wide significant linkage of bipolar disorder to a region on 22q12.3 near the marker D22S278. Towards identifying the susceptibility gene, we have conducted a fine-mapping association study of the region in two independent family samples, an independent case-control sample and a genome-wide association dataset. Two hundred SNPs were first examined in a 5 Mb region surrounding the D22S278 marker in a sample of 169 families and analyzed using PLINK. The peak of association was a haplotype near the genes stargazin (CACNG2), intraflagellar transport protein homolog 27 (IFT27) and parvalbumin (PVALB; P = 4.69 × 10(-4)). This peak overlapped a significant haplotype in a family based association study of a second independent sample of 294 families (P = 1.42 × 10(-5)). Analysis of the combined family sample yielded statistically significant evidence of association to a rare three SNP haplotype in the gene IFT27 (P = 8.89 × 10(-6)). Twelve SNPs comprising these haplotypes were genotyped in an independent sample of 574 bipolar I cases and 550 controls. Statistically significant association was found for a haplotype window that overlapped the region from the first two family samples (P = 3.43 × 10(-4)). However, analyses of the two family samples using the program LAMP, found no evidence for association in this region, but did yield significant evidence for association to a haplotype 3' of CACNG2 (P = 1.76 × 10(-6)). Furthermore, no evidence for association was found in a large genome-wide association dataset. The replication of association to overlapping haplotypes in three independent datasets suggests the presence of a bipolar disorder susceptibility gene in this region.

North Carolina National Guard Integrated Behavioral Health System.

The North Carolina National Guard (NCNG) Integrated Behavioral Health System is designed to systematically bring the best internal and external military resources together to function collaboratively for the betterment of behavioral health assessment, crisis intervention, referral, and case management services available to NCNG service members and their families.

Allele specific analysis of the ADRBK2 gene in lymphoblastoid cells from bipolar disorder patients.

G-protein coupled receptor kinase-3 (GRK3), translated from the gene, ADRBK2 has been implicated as a candidate molecule for bipolar disorder through multiple, converging lines of evidence. In some individuals, the ADRBK2 gene harbors the A-haplotype, a collection of single nucleotide polymorphisms (SNPs) previously associated with an increased risk for bipolar disorder. Because the A-haplotype encompasses the ADRBK2 promoter, we hypothesized that it may alter the regulation of gene expression. Using histone H3 acetylation to infer promoter activity in lymphoblastoid cells from patients with bipolar disorder, we examined the A-haplotype within its genomic context and determined that at least four of its SNPs are present in transcriptionally active portions of the promoter. However, using chromatin immunoprecipitation followed by allele-specific PCR in samples heterozygous for the A-haplotype, we found no evidence of altered levels of acetylated histone H3 at the affected allele compared to the common allele. Similarly, using a transcribed SNP to discriminate expressed ADRBK2 mRNA strands by allele of origin; we found that the A-haplotype did not confer an allelic-expression imbalance. Our data suggest that while the A-haplotype is situated in active regulatory sequence, the risk-associated SNPs do not appear to affect ADRBK2 gene regulation at the level of histone H3 acetylation nor do they confer measurable changes in transcription in lymphoblastoid cells. However, tissue-specific mechanisms by which the A-haplotype could affect ADRBK2 in the central nervous system cannot be excluded.

Brn3a regulates the transition from neurogenesis to terminal differentiation and represses non-neural gene expression in the trigeminal ganglion.

The POU-domain transcription factor Brn3a is expressed in developing sensory neurons at all levels of the neural axis, including the trigeminal ganglion, hindbrain sensory ganglia, and dorsal root ganglia. Changes in global gene expression in the trigeminal ganglion from E11.5 to E13.5 reflect the repression of early neurogenic genes, exit from the cell cycle, and initiation of the expression of definitive markers of sensory function. A majority of these developmental changes are perturbed in the trigeminal ganglia of Brn3a knockout mice. At E13.5, Brn3a(-/-) trigeminal neurons fail to repress a battery of developmental regulators that are highly expressed at E11.5 and are normally down-regulated as development progresses, and also fail to appropriately activate a set of definitive sensory genes. Remarkably, developing Brn3a(-/-) trigeminal neurons also ectopically express multiple regulatory genes associated with cardiac and/or cranial mesoderm development, although definitive myogenic programs are not activated. The majority of these genes are not ectopically expressed in the dorsal root ganglia of Brn3a null mice, perhaps due to redundant mechanisms of repression at spinal levels. These results underscore the importance of gene repression in regulating neuronal development, and the need for unbiased screens in the determination of developmental gene regulatory programs.

Transcription factor expression in lipopolysaccharide-activated peripheral-blood-derived mononuclear cells.

Transcription factors play a key role in integrating and modulating biological information. In this study, we comprehensively measured the changing abundances of mRNAs over a time course of activation of human peripheral-blood-derived mononuclear cells ("macrophages") with lipopolysaccharide. Global and dynamic analysis of transcription factors in response to a physiological stimulus has yet to be achieved in a human system, and our efforts significantly advanced this goal. We used multiple global high-throughput technologies for measuring mRNA levels, including massively parallel signature sequencing and GeneChip microarrays. We identified 92 of 1,288 known human transcription factors as having significantly measurable changes during our 24-h time course. At least 42 of these changes were previously unidentified in this system. Our data demonstrate that some transcription factors operate in a functional range below 10 transcripts per cell, whereas others operate in a range three orders of magnitude greater. The highly reproducible response of many mRNAs indicates feedback control. A broad range of activation kinetics was observed; thus, combinatorial regulation by small subsets of transcription factors would permit almost any timing input to cis-regulatory elements controlling gene transcription.

Integrated model of hepatic and peripheral glucose regulation for estimation of endogenous glucose production during the hot IVGTT.

We have developed a new model to describe endogenous glucose kinetics during a labeled (hot) intravenous glucose tolerance test (IVGTT) to derive a time profile of endogenous glucose production (EGP). We reanalyzed data from a previously published study (P. Vicini, J. J. Zachwieja, K. E. Yarasheski, D. M. Bier, A. Caumo, and C. Cobelli. Am J Physiol Endocrinol Metab 276: E285-E294, 1999), in which insulin-modified [6,6-2H2]glucose-labeled IVGTTs (0.33 g/kg glucose) were performed in 10 normal subjects. In addition, a second tracer ([U-13C]glucose) was infused in a variable rate to clamp the endogenous glucose tracer-to-tracee ratio (TTR). Our new model describing endogenous glucose kinetics was incorporated into the two-compartment hot minimal-model structure. The model gave estimates of glucose effectiveness [1.54 +/- 0.31 (SE) ml x kg(-1) x min(-1)], insulin sensitivity (37.74 +/- 5.23 10(4) dl x kg(-1) x min(-1) x microU(-1) x ml), and a new parameter describing the sensitivity of EGP to the inhibitory effect of insulin (IC50 = 0.0195 +/- 0.0046 min(-1)). The model additionally provided an estimate of the time course of EGP showing almost immediate inhibition, followed by a secondary inhibitory effect caused by infusion of insulin, and a large overshoot as EGP returns to its basal value. Our estimates show very good agreement with those obtained via deconvolution and the model-independent TTR clamp technique. These results suggest that the new integrated model can serve as a simple one-step approach to obtain metabolic indexes while also providing a parametric description of EGP.