Effects Of Changes In Gene Expression Research Articles

Abstract 13453: Estrogen Regulates Expression of Fibrotic Markers in Ips-derived Cardiac Fibroblasts and Cardiomyocytes

Introduction: Cardiovascular disease (CVD) is the leading cause of death among women. Epidemiologic studies indicate that pre-menopausal women are protected against the development of CVD when compared to age-matched men. Women show less cardiac remodeling, with downregulation in fibrosis and inflammation pathways. Remodeling is manifested by morphology and electrophysiological changes including hypertrophy, apoptosis, fibroblast proliferation, fibrosis and accumulation of fibrillar collagens. Hypothesis: We hypothesize that female protection against CVD is associated with estrogen levels as the incidence and severity of CVD increases after menopause. Methods: Induced pluripotent stem cells (IPSC) from male (M) and female (F) controls were differentiated to cardiomyocytes (IPSC-CMs) and cardiac fibroblasts (IPSC-CFs). Samples were cultured for 30 days and collected for analysis before and after 48 hs incubation with 1uM of 17-b-estradiol (EST). In IPSC-CMs we analyzed gene expression, morphology and beating frequency. Gene expression, morphology and wound healing were analyzed in IPSC-CFs. Results: Expression of ESR1 , and MYH7 was higher in female IPSC-CMs with upregulation after EST treatment in females but not males. Male IPSC-CMs showed higher expression of COL1A1 , CX43 , MYH6 and RYR2 ; MYH6 , RYR2 and COL1A1 were downregulated after EST treatment. No differences were observed in morphology or beating frequency before or after EST treatment (F:27.5±4.5 bpm vs M:22±2.5 bpm). In IPSC-CFs, males showed higher expression of the fibrotic markers COL1A1 , POSTN, SMAD2 and CCL2 ; EST treatment decreased the expression of POSTN and SMAD2 . Wound healing assays showed a decrease of the wound healing % in women after EST treatment (CT F:86.4±19.7% vs EST F:57.43±10.1%, at 8 hs, *p<0.05). Male wound healing rate was slower than women in control and treated groups, with no changes after EST treatment (CT F: 86.4±19.7% vs CT M: 51.65±18.4%, at 8 hs, *p<0.05). Conclusions: Estrogen treatment exerts an effect on gene expression in female and male IPSC-CMs and IPSC-CFs with men showing higher expression of fibrotic markers, which are down-regulated by EST. Further functional studies will shed light on the phenotypic effects of gene expression changes.

Statistical analysis of human microarray data shows that dietary intervention with n-3 fatty acids, flavonoids and resveratrol enriches for immune response and disease pathways.

n-3 Fatty acids, flavonoids and resveratrol are well publicised for their beneficial effects on human health and wellbeing. Identifying common, underlying biological mechanisms targeted by these functional foods would therefore be informative for the public health sector for advising on nutritional health and disease, food and drug product development and consumer interest. The aim of this study was to explore the potential effects of gene expression changes associated with n-3 fatty acids EPA and DHA, flavonoids and resveratrol on modifying biological systems and disease pathways. To test this, publicly available human microarray data for significant gene expression changes associated with dietary intervention with EPA/DHA, flavonoids and resveratrol was subjected to pathway analysis and significance testing for overlap with signals from genome-wide association studies (GWAS) for common non-communicable diseases and biological functions. There was an enrichment of genes implicated in immune responses and disease pathways which was common to all of the treatment conditions tested. Analysis of biological functions and disease pathways indicated anti-tumorigenic properties for EPA/DHA. In line with this, significance testing of the intersection of genes associated with these functional foods and GWAS hits for common biological functions (ageing and cognition) and non-communicable diseases (breast cancer, CVD, diabesity, neurodegeneration and psychiatric disorders) identified significant overlap between the EPA/DHA and breast cancer gene sets. Dietary intervention with EPA/DHA, flavonoids and resveratrol can target important biological and disease pathways suggesting a potentially important role for these bioactive compounds in the prevention and treatment of dietary-related diseases.

Multifactorial Origins of Heart and Gut Defects in nipbl-Deficient Zebrafish, a Model of Cornelia de Lange Syndrome

Author SummaryAlthough best known for its role in chromatid cohesion, cohesin is increasingly seen as a regulator of gene expression. In Cornelia de Lange Syndrome (CdLS), partial deficiency for NIPBL, which encodes a cohesin regulator, is associated with small changes in the expression of many genes (similar effects are seen in Nipbl-deficient mice and flies). Are such changes responsible for pervasive developmental defects in CdLS? To address this, we used morpholino oligonucleotides to quantitatively reduce levels of Nipbl protein and Nipbl target genes in zebrafish embryos. Combined knockdown of both zebrafish nipbl genes produced heart and gut defects with similarities to those observed in CdLS. Nipbl-deficient embryos showed quantitative changes in the expression of several genes involved in the specification of endoderm, which both gives rise to gut and provides a substrate for cardiac precursor migration, as well as genes that regulate left-right asymmetry. Functional studies of these putative targets suggest that changes in their expression collectively, and in some cases synergistically, contribute to the observed phenotypes. These findings suggest that birth defects in CdLS result from combinatorial, quantitative effects of NIPBL on gene expression, and suggest that cardiac and visceral organ defects in CdLS arise during early embryonic development.

Cell-cycle gene expression in lovastatin-induced medulloblastoma apoptosis.

3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase is a key rate-limiting enzyme in the mevalonate pathway, which generates precursors both for cholesterol biosynthesis and for the production of nonsteroidal mevalonate derivatives that are involved in a number of growth-regulatory processes. We have reported that lovastatin, a competitive inhibitor of HMG-CoA reductase, not only inhibits medulloblastoma proliferation in vitro, but also induces near-complete cell death via apoptosis. The mechanism of this phenomenon is unclear. Possible involvement of changes in expression of certain cell-cycle related genes led us to study some of them in more detail. Medulloblastoma cell lines were exposed in vitro to lovastatin, and the effects of gene expression changes were studied using RT-PCR, antisense oligonucleotide, DNA electrophoresis and Western blotting analysis. 1) Levels of total Ras gene mRNA and individual Ras gene mRNA are stable in lovastatin treatment in all examined medulloblastoma cell lines. 2) Blocking c-myc gene over-expression does not enhance medulloblastoma cell sensitivity to lovastatin. 3) Following lovastatin treatment, p16 expression exhibits no change, but pronounced increases of p27KIP1 protein are observed in all examined cell lines. Lovastatin induces pronounced increases of p21WAF1 protein only in Daoy and UW228, but not in D283 Med and D341 Med. 4) Following lovastatin treatment, increased p53 protein is detected only in D341 Med, and bax protein is unchanged in all cell lines. Lovastatin-induced growth inhibition and apoptosis in medulloblastoma are not dependent on the regulation of Ras and c-myc gene expression, but may be mediated by p27KIP1 gene expression. Lovastatin-induced apoptosis in medulloblastoma is probably p53 independent, but p53 and p21WAF1 gene expression may also mediate anti-proliferative effects of lovastatin on specific medulloblastoma cell lines.