The gene coding for PGC-1α 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. HD is caused by an unstable CAG repeat expansion in the HD gene (HTT), localized on chromosome 4p16.3. The number of CAG repeats in the HD gene is the main predictor of disease-onset, but the remaining variation is strongly heritable. Transcriptional dysregulation, mitochondrial dysfunction and enhanced oxidative stress have been implicated in the pathogenesis. Recent studies suggest that PGC-1α, a transcriptional master regulator of mitochondrial biogenesis and metabolism, is defective in HD. A genome wide search for modifier genes of HD age-of-onset had suggested linkage at chromosomal region 4p16-4p15, near the locus of PPARGC1A, the gene coding for PGC-1α. We now present data of 2-loci PPARGC1A block 2 haplotypes, showing an effect upon age-at-onset in 447 unrelated HD patients after statistical consideration of CAG repeat lengths in both HTT alleles. Block 1 haplotypes were not associated with the age-at-onset. Homozygosity for the 'protective' block 2 haplotype was associated with a significant delay in disease onset. To our knowledge this is the first study to show clinically relevant effects of the PGC-1α system on the course of Huntington's disease in humans

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. Symptom onset is typically between 40 and 50 years of age, but can vary by several decades in extreme cases and this is in part determined by modifying genetic factors. The metabolic master regulator PGC-1α, coded by the PPARGC1A gene, coordinates cellular respiration and was shown to play a role in neurodegenerative diseases, including HD. METHODS: Using a candidate gene approach we analyzed a large European cohort (n = 1706) from the REGISTRY study for associations between PPARGC1A genotype and age at onset (AO) in HD. RESULTS: We report that a coding variant (rs3736265) in PPARGC1A is associated with an earlier motor AO in men but not women carrying the HD mutation. CONCLUSIONS: These results further strengthen the evidence for a role of PGC-1α in HD and unexpectedly suggest a gender effect

A TOMM40/APOE

Abstract 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 0.02. The two haplotypes encoding APOE‐E4 showed strong associations with AD that did not differ between intermediate and high likelihood AD. In contrast, a TOMM40 haplotype encoding APOE‐E3 was identified as risk haplotype of high‐ (p = .0186), but not intermediate likelihood AD (p = .7530). Furthermore, the variant allele of rs2075650 located in intron 2 of TOMM40, increased the risk of high‐, but not intermediate likelihood AD on the APOE‐ε3/ε3 background (p = .0230). Conclusion The striking association of TOMM40 only with high likelihood AD may explain some contrasting results for TOMM40 in clinical studies and may reflect an association with more advanced disease and/or suggest a role of TOMM40 in the pathogenesis of neurofibrillary tangles

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

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. Methods: Real-time PCR and pyrosequencing were used to respectively quantify pendrin mRNA levels and methylation of pendrin promoter, with and without IL-4 stimulation, in healthy and diseased primary HBE cells, as well as NCI-H292 cells. Results: Increases in pendrin mRNA after IL-4 stimulation was more robust in NCI-H292 cells than in primary cells. The amount of gDNA methylated varied greatly between the cell types. In particular, CpG site 90 located near the N4 GAS motif was highly methylated in the primary cells. An additional CpG site (90bis), created by a SNP, was found only in the primary cells. IL-4 stimulation resulted in dramatic demethylation of CpG sites 90 and 90bis in the primary cells. Conclusions: IL-4 induces demethylation of specific CpG sites within the pendrin promoter. These epigenetic alterations are cell type specific, and may in part dictate pendrin mRNA transcription

Steroid Receptor Coactivator 2 Is Critical for Progesterone-Dependent Uterine Function and Mammary Morphogenesis in the Mouse

Although the essential involvement of the progesterone receptor (PR) in female reproductive tissues is firmly established, the coregulators preferentially enlisted by PR to mediate its physiological effects have yet to be fully delineated. To further dissect the roles of members of the steroid receptor coactivator (SRC)/p160 family in PR-mediated reproductive processes in vivo, state-of-the-art cre-loxP engineering strategies were employed to generate a mouse model (PR(Cre/+) SRC-2(flox/flox)) in which SRC-2 function was abrogated only in cell lineages that express the PR. Fertility tests revealed that while ovarian activity was normal, PR(Cre/+) SRC-2(flox/flox) mouse uterine function was severely compromised. Absence of SRC-2 in PR-positive uterine cells was shown to contribute to an early block in embryo implantation, a phenotype not shared by SRC-1 or -3 knockout mice. In addition, histological and molecular analyses revealed an inability of the PR(Cre/+) SRC-2(flox/flox) mouse uterus to undergo the necessary cellular and molecular changes that precede complete P-induced decidual progression. Moreover, removal of SRC-1 in the PR(Cre/+) SRC-2(flox/flox) mouse uterus resulted in the absence of a decidual response, confirming that uterine SRC-2 and -1 cooperate in P-initiated transcriptional programs which lead to full decidualization. In the case of the mammary gland, whole-mount and histological analysis disclosed the absence of significant ductal side branching and alveologenesis in the hormone-treated PR(Cre/+) SRC-2(flox/flox) mammary gland, reinforcing an important role for SRC-2 in cellular proliferative changes that require PR. We conclude that SRC-2 is appropriated by PR in a subset of transcriptional cascades obligate for normal uterine and mammary morphogenesis and function

Progesterone receptor function is required for mammary ductal side-branching and alveologenesis

<p><b>Copyright information:</b></p><p>Taken from "Progesterone receptors - animal models and cell signaling in breast cancer: Progesterone's role in mammary gland development and tumorigenesis as disclosed by experimental mouse genetics"</p><p>Breast Cancer Research 2002;4(5):191-196.</p><p>Published online 5 Jul 2002</p><p>PMCID:PMC138743.</p><p>Copyright © 2002 BioMed Central Ltd</p> The salient postnatal stages of mammary gland development. Whole mounts of transplanted progesterone receptor knockout (PRKO) mammary glands and wild-type mammary glands taken from a nulliparous host, and transplanted PRKO mammary glands and wild-type mammary glands taken from a parous host. Scale bar in (b) denotes 500 m and applies to all whole mounts. Adapted from Lydon . []