Tuesday, December 30, 2014

skin cells transformed into egg and sperm, epigenetic changes can be REMOVED

The Guardian | Scientists have made primitive forms of artificial sperm and eggs in a medical feat that could transform the understanding of age-related diseases and fertility problems.
Researchers in Cambridge made the early-stage sex cells by culturing human embryonic stem cells under carefully-controlled conditions for a week.
They followed the success by showing that the same procedure can convert adult skin tissue into precursors for sperm and eggs, raising the prospect of making sex cells that are genetically matched to patients.
The cells should have the potential to grow into mature sperm and eggs, though this has never been done in the lab before. The next step for the researchers will be to inject the cells into mouse ovaries or testes to see if they fully develop in the animals.
Perhaps more intriguingly, the cells may hold the secrets for treating certain age-related diseases. As people age they accumulate not only genetic mutations, but other changes to their DNA. These epigenetic changes can be caused by smoking, exposure to chemicals in the environment, or diet and other lifestyle factors. But the cells that form sperm and eggs are wiped clean of their epigenetic changes early on. “This could tell us how to erase these epigenetic mutations. Epigenetics is used to regulate gene expression, but in age-related diseases, these changes can be aberrant and misregulate genes,” Surani said.

Friday, December 19, 2014

exercise changes your dna

PLoS Genet | A sedentary lifestyle, a poor diet and new technologies that reduce physical activity cause health problems worldwide, as reduced energy expenditure together with increased energy intake lead to weight gain and increased cardiometabolic health risks . Obesity is an important predictor for the development of both type 2 diabetes (T2D) and cardiovascular diseases, which suggests a central role for adipose tissue in the development of these conditions . Adipose tissue is an endocrine organ affecting many metabolic pathways, contributing to total glucose homeostasis . T2D is caused by a complex interplay of genetic and lifestyle factors , and a family history of T2D has been associated with reduced physical fitness and an increased risk of the disease . Individuals with high risk of developing T2D strongly benefit from non-pharmacological interventions, involving diet and exercise . Exercise is important for physical health, including weight maintenance and its beneficial effects on triglycerides, cholesterol and blood pressure, suggestively by activating a complex program of transcriptional changes in target tissues.
Epigenetic mechanisms such as DNA methylation are considered to be important in phenotype transmission and the development of different diseases . The epigenetic pattern is mainly established early in life and thereafter maintained in differentiated cells, but age-dependent alterations still have the potential to modulate gene expression and translate environmental factors into phenotypic traits . In differentiated mammalian cells, DNA methylation usually occurs in the context of CG dinucleotides (CpGs) and is associated with gene repression . Changes in epigenetic profiles are more common than genetic mutations and may occur in response to environmental, behavioural, psychological and pathological stimuli. Furthermore, genetic variation not associated with a phenotype could nonetheless affect the extent of variability of that phenotype through epigenetic mechanisms, such as DNA methylation. It is not known whether epigenetic modifications contribute to the cause or transmission of T2D between generations. Recent studies in human skeletal muscle and pancreatic islets point towards the involvement of epigenetic modifications in the regulation of genes important for glucose metabolism and the pathogenesis of T2D ,. However, there is limited information about the regulation of the epigenome in human adipose tissue .
The mechanisms behind the long-lasting effects of regular exercise are not fully understood, and most studies have focused on cellular and molecular changes in skeletal muscle. Recently, a global study of DNA methylation in human skeletal muscle showed changes in the epigenetic pattern in response to long-term exercise . The aims of this study were to: 1) explore genome-wide levels of DNA methylation before and after a six months exercise intervention in adipose tissue from healthy, but previously sedentary men; 2) investigate the differences in adipose tissue DNA methylation between individuals with or without a family history of T2D; 3) relate changes in DNA methylation to adipose tissue mRNA expression and metabolic phenotypes in vitro.

Sunday, December 14, 2014

yet another potential danger of genetically modified food organisms

theatlantic | Chinese researchers have found small pieces of rice ribonucleic acid (RNA) in the blood and organs of humans who eat rice. The Nanjing University-based team showed that this genetic material will bind to receptors in human liver cells and influence the uptake of cholesterol from the blood.

The type of RNA in question is called microRNA (abbreviated to miRNA) due to its small size. MiRNAs have been studied extensively since their discovery ten years ago, and have been implicated as players in several human diseases including cancer, Alzheimer's, and diabetes. They usually function by turning down or shutting down certain genes. The Chinese research provides the first in vivo example of ingested plant miRNA surviving digestion and influencing human cell function in this way.

Should the research survive scientific scrutiny -- a serious hurdle -- it could prove a game changer in many fields. It would mean that we're eating not just vitamins, protein, and fuel, but gene regulators as well.

That knowledge could deepen our understanding of many fields, including cross-species communication, co-evolution, and predator-prey relationships. It could illuminate new mechanisms for some metabolic disorders and perhaps explain how some herbal and modern medicines function.
This study had nothing to do with genetically modified (GM) food, but it could have implications on that front. The work shows a pathway by which new food products, such as GM foods, could influence human health in previously unanticipated ways.

Monsanto's website states, "There is no need for, or value in testing the safety of GM foods in humans." This viewpoint, while good for business, is built on an understanding of genetics circa 1960. It follows what's called the "Central Dogma" of genetics, which postulates a one-way chain of command between DNA and the cells DNA governs.