Hiển thị các bài đăng có nhãn genetic. Hiển thị tất cả bài đăng
Hiển thị các bài đăng có nhãn genetic. Hiển thị tất cả bài đăng

Thứ Bảy, 25 tháng 3, 2017

Model of Anorexia Created Using Stem Cells

Though often viewed as a non-biological disorder, new research suggests 50 to 75 percent of risk for AN may be heritable; with predisposition driven primarily by genetics and not, as sometimes presumed, by vanity, poor parenting or factors related to specific groups of individuals. NeuroscienceNews.com image is for illustrative purposes only.

Findings suggest a strong genetic factor could predispose people to anorexia and other eating disorders. Technique suggests novel gene may contribute to eating disorder.



An international research team, led by scientists at University of California San Diego School of Medicine, has created the first cellular model of anorexia nervosa (AN), reprogramming induced pluripotent stem cells (iPSCs) derived from adolescent females with the eating disorder.

Writing in the March 14th issue of Translational Psychiatry, the scientists said the resulting AN neurons — the disease in a dish — revealed a novel gene that appears to contribute to AN pathophysiology, buttressing the idea that AN has a strong genetic factor. The proof-of-concept approach, they said, provides a new tool to investigate the elusive and largely unknown molecular and cellular mechanisms underlying the disease.

“Anorexia is a very complicated, multifactorial neurodevelopmental disorder,” said Alysson Muotri, PhD, professor in the UC San Diego School of Medicine departments of Pediatrics and Cellular and Molecular Medicine, director of the UC San Diego Stem Cell Program and a member of the Sanford Consortium for Regenerative Medicine. “It has proved to be a very difficult disease to study, let alone treat. We don’t actually have good experimental models for eating disorders. In fact, there are no treatments to reverse AN symptoms.”



Primarily affecting young female adolescents between ages 15 and 19, AN is characterized by distorted body image and self-imposed food restriction to the point of emaciation or death. It has the highest mortality rate among psychiatric conditions. For females between 15 and 24 years old who suffer from AN, the mortality rate associated with the illness is 12 times higher than the death rate of all other causes of death.

Though often viewed as a non-biological disorder, new research suggests 50 to 75 percent of risk for AN may be heritable; with predisposition driven primarily by genetics and not, as sometimes presumed, by vanity, poor parenting or factors related to specific groups of individuals.

But little is actually known about the molecular, cellular or genetic elements or genesis of AN. In their study, Muotri and colleagues at UC San Diego and in Brazil, Australia and Thailand, took skin cells from four females with AN and four healthy controls, generated iPSCs (stem cells with the ability to become many types of cells) from these cells and induce these iPSCs to become neurons.



(Previously, Muotri and colleagues had created stem cell-derived neuronal models of autism and Williams syndrome, a rare genetic neurological condition.)

Then they performed unbiased comprehensive whole transcriptome and pathway analyses to determine not just which genes were being expressed or activated in AN neurons, but which genes or transcripts (bits of RNA used in cellular messaging) might be associated with causing or advancing the disease process.

No predicted differences in neurotransmitter levels were observed, the researchers said, but they did note disruption in the Tachykinin receptor 1 (TACR1) gene. Tachykinins are neuropeptides or proteins expressed throughout the nervous and immune systems, where they participate in many cellular and physiological processes and have been linked to multiple diseases, including chronic inflammation, cancer, infection and affective and addictive disorders.

The scientists posit that disruption of the tachykinin system may contribute to AN before other phenotypes or observed characteristics become obvious, but said further studies employing larger patient cohorts are necessary.



“But more to the point, this work helps make that possible,” said Muotri. “It’s a novel technological advance in the field of eating disorders, which impacts millions of people. These findings transform our ability to study how genetic variations alter brain molecular pathways and cellular networks to change risk of AN — and perhaps our ability to create new therapies.”
Source: NEUROSCIENCE NEWS

YOUR INPUT IS MUCH APPRECIATED! LEAVE YOUR COMMENT BELOW.

Thứ Sáu, 9 tháng 12, 2016

Biologists unlock 51.7-million-year-old genetic secret to landmark Darwin theory

Scientists have identified the cluster of genes responsible for reproductive traits in the Primula flower, first noted as important by Charles Darwin more than 150 years ago. Darwin hypothesized that some plant species with two distinct forms of flower, where male and female reproductive organs were of differing lengths, had evolved that way to promote out-crossing by insect pollinators.

His ground-breaking insight into the significance of the two forms of flower known as 'pins' and 'thrums' coined the term 'heterostyly', and subsequent studies contributed to the foundation of modern genetic theory.

And now scientists at the University of East Anglia, working at the John Innes Centre, have identified exactly which part of these species' genetic code made them that way, through an event that occurred more than 51 million years ago.
Prof Philip Gilmartin from UEA's School of Biological Sciences said: "To identify the genes which control the biology noted by Darwin is an exciting moment. Many studies have been done over the past decades to explore the genetic basis of this phenomenon but now we have pinpointed the supergene directly responsible, the S locus."



Supergenes are clusters of closely-associated genes which are always inherited together as a unit and allow complex biology to be controlled. Researchers worked with the Earlham Institute to map the plant's genes and sequence the Primula genome to find the specific gene cluster responsible for creating the differing flower morphs.

Prof Gilmartin said: "Not only did we identify the supergene but we found it is specific to just one of the flower forms, the thrum. This insight has profound implications for our understanding of a key evolutionary innovation of flowering plants.
"Understanding of the genetics which underpin flower development and reproduction of a species broadens our knowledge about the entire system of pollination, which underpins biodiversity and food security.

"With challenges such as climate change and its effects on plants, crops and their insect pollinators, it's even more important to understand pollination mechanisms and how species can and will react.
In their hunt for the genes controlling heterostyly, researchers also managed to date the original mutation, to 51.7 million years ago.

Having found the S locus, they realized the gene was a close relative to another, identified six years ago as responsible for controlling the identity of petals on a Primula flower. At some point this gene duplicated, inserted itself in the S locus, and mutated to control the position of the anther in the flower. Finding this duplicated gene allowed the team to date how long ago the mutation occurred for the first time.



Prof Gilmartin has been researching the origins of heterostyly for a large part of his career. He said: "This study answers some of the crucial questions that have been asked since Darwin's time, and for me since I bought my first packet of Primula seeds twenty years ago."

The study 'Genetic architecture and evolution of the S locus supergene in Primula vulgaris' is published in the journal Nature Plants, on Friday 2 December 2016.

Sources: ‘How 16th Century observations paved the way for Darwin's landmark study’
More information: Jinhong Li et al. Genetic architecture and evolution of the S locus supergene in Primula vulgaris, Nature Plants (2016). DOI: 10.1038/nplants.2016.188
Journal reference: Nature Plants
Provided by: University of East Angli

YOUR INPUT IS MUCH APPRECIATED! LEAVE YOUR COMMENT BELOW.

 
OUR MISSION