Selective Activation of CNS and Reference Promoters Is Associated with Distinct Gene Programs Relevant for Neurodegenerative Diseases.

The transcriptional regulator peroxisome proliferator activated receptor gamma coactivator 1A (PGC-1α), encoded by , has been linked to neurodegenerative diseases. Recently discovered CNS-specific transcripts are initiated far upstream of the reference promoter, spliced to exon 2 of the reference gene, and are more abundant than reference gene transcripts in post-mortem human brain samples. The proteins translated from the CNS and reference transcripts differ only at their N-terminal regions.

A TOMM40/APOE allele encoding APOE-E3 predicts high likelihood of late-onset Alzheimer's disease in autopsy cases.

Background: The APOE-ε4 allele is an established risk factor for Alzheimer's disease (AD). TOMM40 located adjacent to APOE has also been implicated in AD but reports of TOMM40 associations with AD that are independent of APOE-ε4 are at variance.

Methods: We investigated associations of AD with haplotypes defined by three TOMM40 and two APOE single nucleotide polymorphisms in 73 and 71 autopsy cases with intermediate and high likelihood of AD (defined by BRAAK stages View Article and Find Full Text PDF

The Expression of CNS-Specific PPARGC1A Transcripts Is Regulated by Hypoxia and a Variable GT Repeat Polymorphism.

PPARGC1A encodes a transcriptional co-activator also termed peroxisome proliferator-activated receptor (PPAR) gamma coactivator 1-alpha (PGC-1α) which orchestrates multiple transcriptional programs. We have recently identified CNS-specific transcripts that are initiated far upstream of the reference gene (RG) promoter. The regulation of these isoforms may be relevant, as experimental and genetic studies implicated the PPARGC1A locus in neurodegenerative diseases.

The PPARGC1A locus and CNS-specific PGC-1α isoforms are associated with Parkinson's Disease.

Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide. PGC-1α, encoded by PPARGC1A, is a transcriptional co-activator that has been implicated in the pathogenesis of neurodegenerative disorders. We recently discovered multiple new PPARGC1A transcripts that initiate from a novel promoter located far upstream of the reference gene promoter, are CNS-specific and are more abundant than reference gene transcripts in whole brain.

Interleukin-4 Induces CpG Site-Specific Demethylation of the Pendrin Promoter in Primary Human Bronchial Epithelial Cells.

Unlabelled: Pendrin is upregulated in bronchial epithelial cells following IL-4 stimulation via binding of STAT6 to an N4 GAS motif. Basal CpG methylation of the pendrin promoter is cell-specific. We studied if a correlation exists between IL-4 sensitivity and the CpG methylation status of the pendrin promoter in human bronchial epithelial cell models.

Specific circulating phospholipids, acylcarnitines, amino acids and biogenic amines are aerobic exercise markers.

Objectives: Regular aerobic exercise provides beneficial effects on human health and reduces all-cause mortality. Aerobic exercise has profound metabolic effects, and specific metabolites may reflect physiological changes. We aimed to identify endogenous metabolites that distinguish the trained from the untrained state to increase the spectrum of analytes amenable for hypothesis testing and to expand understanding of putative beneficial pathways.

Associations of Haplotypes Upstream of IRS1 with Insulin Resistance, Type 2 Diabetes, Dyslipidemia, Preclinical Atherosclerosis, and Skeletal Muscle LOC646736 mRNA Levels.

The genomic region ~500 kb upstream of IRS1 has been implicated in insulin resistance, type 2 diabetes, adverse lipid profile, and cardiovascular risk. To gain further insight into this chromosomal region, we typed four SNPs in a cross-sectional cohort and subjects with type 2 diabetes recruited from the same geographic region. From 16 possible haplotypes, 6 haplotypes with frequencies >0.

Targeting SREBPs for treatment of the metabolic syndrome.

Over the past few decades, mortality resulting from cardiovascular disease (CVD) steadily decreased in western countries; however, in recent years, the decline has become offset by the increase in obesity. Obesity is strongly associated with the metabolic syndrome and its atherogenic dyslipidemia resulting from insulin resistance. While lifestyle treatment would be effective, drugs targeting individual risk factors are often required.

Heme oxygenase-1 drives metaflammation and insulin resistance in mouse and man.

Obesity and diabetes affect more than half a billion individuals worldwide. Interestingly, the two conditions do not always coincide and the molecular determinants of "healthy" versus "unhealthy" obesity remain ill-defined. Chronic metabolic inflammation (metaflammation) is believed to be pivotal.

The human pendrin promoter contains two N(4) GAS motifs with different functional relevance.

Background: Pendrin, an anion exchanger associated with the inner ear, thyroid and kidney, plays a significant role in respiratory tissues and diseases, where its expression is increased following IL-4 and IL-13 exposure. The mechanism leading to increased pendrin expression is in part due to binding of STAT6 to a consensus sequence (N4 GAS motif) located in the pendrin promoter. As retrospective analyses of the 5' upstream sequence of the human pendrin promoter revealed an additional N4 GAS motif (1660 base pairs upstream of the one previously identified), we set out to define its contribution to IL-4 stimulated changes in pendrin promoter activity.

Use of the operon structure of the C. elegans genome as a tool to identify functionally related proteins.

One of the most pressing challenges in the post genomic era is the identification and characterization of protein-protein interactions (PPIs), as these are essential in understanding the cellular physiology of health and disease. Experimental techniques suitable for characterizing PPIs (X-ray crystallography or nuclear magnetic resonance spectroscopy, among others) are usually laborious, time-consuming and often difficult to apply to membrane proteins, and therefore require accurate prediction of the candidate interacting partners. High-throughput experimental methods (yeast two-hybrid and affinity purification) succumb to the same shortcomings, and can also lead to high rates of false positive and negative results.

A single nucleotide polymorphism in the coding region of PGC-1α is a male-specific modifier of Huntington disease age-at-onset in a large European cohort.

Background: Genetic modifiers are important clues for the identification of therapeutic targets in neurodegenerative diseases. Huntington disease (HD) is one of the most common autosomal dominant inherited neurodegenerative diseases. The clinical symptoms include motor abnormalities, cognitive decline and behavioral disturbances.

PGC-1α is a male-specific disease modifier of human and experimental amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a devastating, adult-onset neurodegenerative disorder of the upper and lower motor systems. It leads to paresis, muscle wasting and inevitably to death, typically within 3-5 years. However, disease onset and survival vary considerably ranging in extreme cases from a few months to several decades.

Glucose acts as a regulator of serum iron by increasing serum hepcidin concentrations.

Mutual clinical and molecular interactions between iron and glucose metabolism have been reported. We aimed to investigate a potential effect of glucose on iron homeostasis. We found that serum iron concentrations gradually decreased over 180 min after the administration of 75 g of glucose from 109.

A greatly extended PPARGC1A genomic locus encodes several new brain-specific isoforms and influences Huntington disease age of onset.

PGC-1α has been implicated in the pathogenesis of neurodegenerative disorders. Several single-nucleotide polymorphisms (SNPs) located in two separate haplotype blocks of PPARGC1A have shown associations with Huntington's disease (HD) and Parkinson's disease, but causative SNPs have not been identified. One SNP (rs7665116) was located in a highly conserved 233 bp region of intron 2.

Potential role of upstream stimulatory factor 1 gene variant in familial combined hyperlipidemia and related disorders.

Objective: Genetic studies implicated upstream stimulatory factor 1 (USF1) in familial combined hyperlipidemia because the rs2073658 minor allele was associated with reduced risk of familial combined hyperlipidemia and related disorders. The molecular mechanisms whereby rs2073658 influences trait expression have remained elusive.

Methods And Results: Plasma lipids, rs2073658 genotypes (N=372), and hepatic transcript levels (N=96) of USF1 and genes involved in hepatic lipoprotein production were determined in obese subjects.

Cholesteryl ester transfer protein and hepatic lipase gene polymorphisms: effects on hepatic mRNA levels, plasma lipids and carotid atherosclerosis.

Objective: HDL modifying effects of cholesteryl ester transfer protein (CETP) and hepatic lipase (LIPC) depend in part on each other. We studied associations of CETP-Taq1B and -514C>T-LIPC polymorphisms with hepatic mRNA levels, and their combined effects on plasma lipids and carotid atherosclerosis.

Methods: We genotyped the CETP-Taq1B and the -514C>T-LIPC polymorphisms in 67 obese women in whom hepatic CETP and LIPC transcript levels were determined as well as in 1549 participants of the Salzburg Atherosclerosis Prevention Program in Subjects at High Individual Risk (SAPHIR).

A mouse transgenic approach to induce β-catenin signaling in a temporally controlled manner.

Although constitutive murine transgenic models have provided important insights into β-catenin signaling in tissue morphogenesis and tumorigenesis, these models are unable to express activated β-catenin in a temporally controlled manner. Therefore, to enable the induction (and subsequent de-induction) of β-catenin signaling during a predetermined time-period or developmental stage, we have generated and characterized a TETO-ΔN89β-catenin responder transgenic mouse. Crossed with the MTB transgenic effector mouse, which targets the expression of the reverse tetracycline transactivator (rtTA) to the mammary epithelium, we demonstrate that the stabilized (and activated) form of β-catenin (ΔN89β-catenin) is expressed only in the presence doxycycline-activated rtTA in the mammary epithelial compartment.

Targeting RANKL to a specific subset of murine mammary epithelial cells induces ordered branching morphogenesis and alveologenesis in the absence of progesterone receptor expression.

Despite support for receptor of activated NF-κB ligand (RANKL) as a mediator of mammary progesterone action, the extent to which this cytokine can functionally contribute to established progesterone-induced mammary morphogenetic responses in the absence of other presumptive effectors is still unclear. To address this uncertainty, we developed an innovative bigenic system for the doxycycline-inducible expression of RANKL in the mammary epithelium of the progesterone receptor knockout (PRKO) mouse. In response to acute doxycycline exposure, RANKL is specifically expressed in the estrogen receptor α (ER) positive/progesterone receptor negative (ER(+)/PR(-)) cell type in the PRKO mammary epithelium, a cell type that is equivalent to the ER(+)/PR(+) cell type in the wild-type (WT) mammary epithelium.

Aberrant hepatic TRIB3 gene expression in insulin-resistant obese humans.

Aims/hypothesis: The pseudokinase tribbles homologue 3 (Drosophila) (TRIB3) negatively interferes with insulin-mediated phosphorylation and activation of v-akt murine thymoma viral oncogene homologue 1 (AKT1, also known as protein kinase B). Animal studies have shown that Trib3 expression was higher in the fasting state and in animal models of diabetes, promoting hyperglycaemia presumably by increasing glucose production in the liver. Less is known about the role of TRIB3 in insulin resistance in humans, although a gain-of-function mutation associated with abnormalities related to insulin resistance has been described in TRIB3.

Hepatic adiponectin receptors (ADIPOR) 1 and 2 mRNA and their relation to insulin resistance in obese humans.

Objective: Adiponectin signalling attenuates insulin resistance (IR) and steatosis hepatis in animal models. As adiponectin receptor (ADIPOR)1 and ADIPOR2 are critical components in the adiponectin signalling cascade, we studied hepatic ADIPOR1/2 mRNA levels in humans and their relation to IR.

Design: We determined metabolic risk factors and levels of hepatic mRNA transcribed from ADIPOR1, ADIPOR2 and FOXO1, a putative up-stream regulator, in 43 and 34 obese subjects with low and high homeostasis model assessment-IR, respectively.

A mouse model to dissect progesterone signaling in the female reproductive tract and mammary gland.

Considering the regulatory complexities of progesterone receptor (PR) action throughout the female reproductive axis and mammary gland, we generated a mouse model that enables conditional ablation of PR function in a spatiotemporal specific manner. Exon 2 of the murine PR gene was floxed to generate a conditional PR allele (PR(flox)) in mice. Crossing the PR(flox/flox) mouse with the ZP3-cre transgenic demonstrated that the PR(flox) allele recombines to a PR null allele (PR(d)).

The gene coding for PGC-1alpha modifies age at onset in Huntington's Disease.

Huntington's disease (HD) is one of the most common autosomal dominant inherited, neurodegenerative disorders. It is characterized by progressive motor, emotional and cognitive dysfunction. In addition metabolic abnormalities such as wasting and altered energy expenditure are increasingly recognized as clinical hallmarks of the disease.