Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Genetic risk and stressful early infancy join to increase risk for schizophrenia

Human genome and mouse studies identify new precise genetic links

Working with genetically engineered mice and the genomes of thousands of people with schizophrenia, researchers at Johns Hopkins say they now better understand how both nature and nurture can affect one's risks for schizophrenia and abnormal brain development in general.

The researchers reported in the March 2 issue of Cell that defects in a schizophrenia-risk genes and environmental stress right after birth together can lead to abnormal brain development and raise the likelihood of developing schizophrenia by nearly one and half times.

"Our study suggests that if people have a single genetic risk factor alone or a traumatic environment in very early childhood alone, they may not develop mental disorders like schizophrenia," says Guo-li Ming, M.D., Ph.D., professor of neurology and member of the Institute for Cell Engineering at the Johns Hopkins University School of Medicine. "But the findings also suggest that someone who carries the genetic risk factor and experiences certain kinds of stress early in life may be more likely to develop the disease."

Pinpointing the cause or causes of schizophrenia has been notoriously difficult, owing to the likely interplay of multiple genes and environmental triggers, Ming says. Searching for clues at the molecular level, the Johns Hopkins team focused on the interaction of two factors long implicated in the disease: Disrupted-in-Schizophrenia 1 (DISC1) protein, which is important for brain development, and GABA, a brain chemical needed for normal brain function.

To find how these factors impact brain development and disease susceptibility, the researchers first engineered mice to have reduced levels of DISC1 protein in one type of neuron in the hippocampus, a region of the brain involved in learning, memory and mood regulation. Through a microscope, they saw that newborn mouse brain cells with reduced levels of DISC1 protein had similar sized and shaped neurons as those from mice with normal levels of DISC1 protein. To change the function of the chemical messenger GABA, the researchers engineered the same neurons in mice to have more effective GABA. Those brain cells looked much different than normal neurons, with longer appendages or projections. Newborn mice engineered with both the more effective GABA and reduced levels of DISC1 showed the longest projections, suggesting, Ming said, that defects in both DISC1 and GABA together could change the physiology of developing neurons for the worse.

Meanwhile, other researchers at University of Calgary and at the National Institute of Physiological Sciences in Japan had shown in newborn mice that changes in environment and routine stress can impede GABA from working properly during development. In the next set of experiments, the investigators paired reducing DISC1 levels and stress in mice to see if it could also lead to developmental defects. To stress the mice, the team separated newborns from their mothers for three hours a day for ten days, then examined neurons from the stressed newborns and saw no differences in their size, shape and organization compared with unstressed mice. But when they similarly stressed newborn mice with reduced DISC1 levels, the neurons they saw were larger, more disorganized and had more projections than the unstressed mouse neurons. The projections, in fact, went to the wrong places in the brain.

Next, to see if their results in mice correlated to suspected human schizophrenia risk factors, the researchers compared the genetic sequences of 2,961 schizophrenia patients and healthy people from Scotland, Germany and the United States. Specifically, they determined if specific variations of DNA letters found in two genes, DISC1 and a gene for another protein, NKCC1, which controls the effect of GABA, were more likely to be found in schizophrenia patients than in healthy individuals. They paired 36 DNA "letter" changes in DISC1 and two DNA letter variations in NKCC1 — one DNA letter change per gene — in all possible combinations. Results showed that if a person's genome contained one specific combination of single DNA letter changes, then that person is 1.4 times more likely than people without these DNA changes to develop schizophrenia. Having these single DNA letter changes in either one of these genes alone did not increase risk.

"Now that we have identified the precise genetic risks, we can rationally search for drugs that correct these defects," says Hongjun Song, Ph.D., co-author, professor of neurology and director of the Stem Cell Program at the Institute for Cell Engineering.

Other authors of the paper from Johns Hopkins are Ju Young Kim, Cindy Y. Liu, Fengyu Zhang, Xin Duan, Zhexing Wen, Juan Song, Kimberly Christian and Daniel R. Weinberger. Emer Feighery, Bai Lu and Joseph H. Callicott from the National Institute of Mental Health, Dan Rujescu of Ludwig-Maximilians-University, and David St Clair of the University of Aberdeen Royal Cornhill Hospital are additional authors.

The study was funded by the National Institutes of Health, the Maryland Stem Cell Research Foundation, the Brain and Behavior Research Foundation and the International Mental Health Research Organization.

Related Stories: Schizophrenia: Small Genetic Changes Pose Risk For Disease:

Johns Hopkins Team Creates Stem Cells From Schizophrenia Patients:

New "Schizophrenia Gene" Prompts Researchers To Test Potential Drug Target:

Normal Role for Schizophrenia Risk Gene Identified:

On the Web: Hongjun Song:

Guo-li Ming:

Institute for Cell Engineering:

Johns Hopkins Medicine
Media Relations and Public Affairs
Media Contacts:
Vanessa McMains; 410-502-9410;
Audrey Huang; 410-614-5105;

Vanessa McMains | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>