Schizophrenia Symptoms Eliminated in Mice Model

Scientists have shown in mice models that overexpression of a gene associated with schizophrenia causes classic symptoms of the disorder that are reversed when gene expression returns to normal.

They genetically engineered mice so they could turn up levels of neuregulin-1 to mimic high levels found in some patients then return levels to normal, said Dr. Lin Mei, Director of the Institute of Molecular Medicine and Genetics at the Medical College of Georgia at Georgia Regents University.

For Stroke-related Disabilities Regenerating Spinal Cord Fibers Could be A Solution
A study has found substantial evidence that a regenerative process involving damaged nerve fibers in the spinal cord could hold the key to better functional recovery by most stroke victims.

They found that when elevated, mice were hyperactive, couldn't remember what they had just learned and couldn't ignore distracting background or white noise. When they returned neuregulin-1 levels to normal in adult mice, the schizophrenia-like symptoms went away, said Mei, corresponding author of the study.

While schizophrenia is generally considered a developmental disease that surfaces in early adulthood, Mei and his colleagues found that even when they kept neuregulin-1 levels normal until adulthood, mice still exhibited schizophrenia-like symptoms once higher levels were expressed. Without intervention, they developed symptoms at about the same age humans do.

"This shows that high levels of neuregulin-1 are a cause of schizophrenia, at least in mice, because when you turn them down, the behavior deficit disappears. Our data certainly suggests that we can treat this cause by bringing down excessive levels of neuregulin-1 or blocking its pathologic effects," Mei said.

Defective Processes in Removing Cellular Waste Reason Behind Neurodegeneration in Gaucher Disease
A new study reveals that the neurodegeneration caused by Gaucher disease is due to defects in the processes that break down and remove unwanted material from the cells.

Schizophrenia is a spectrum disorder with multiple causes - most of which are unknown - that tends to run in families, and high neuregulin-1 levels have been found in only a minority of patients. To reduce neuregulin-1 levels in those individuals likely would require development of small molecules that could, for example, block the gene's signaling pathways, Mei said.

Current therapies treat symptoms and generally focus on reducing the activity of two neurotransmitters since the bottom line is excessive communication between neurons.

Genetic Suspects in Sporadic Lou Gehrig's Disease Identified
Mutations in several new genes that might be associated with the development of amyotrophic lateral sclerosis, or ALS have been discovered by scientists.

The good news is it's relatively easy to measure neuregulin-1 since blood levels appear to correlate well with brain levels. To genetically alter the mice, they put a copy of the neuregulin-1 gene into mouse DNA then, to make sure they could control the levels, they put in front of the DNA a binding protein for doxycycline, a stable analogue for the antibiotic tetracycline, which is infamous for staining the teeth of fetuses and babies.

The mice are born expressing high levels of neuregulin-1 and giving the antibiotic restores normal levels.

New 1-step Genetic Engineering Technology
The workhorses of biotechnology, scientists are reporting that a new streamlined approach to genetic engineering drastically reduces the time and effort needed to insert new genes into bacteria.

"If you don't feed the mice tetracycline, the neuregulin-1 levels are always high," said Mei, noting that endogenous levels of the gene are not affected. High-levels of neuregulin-1 appear to activate the kinase LIMK1, impairing release of the neurotransmitter glutamate and normal behavior. The LIMK1 connection identifies another target for intervention, Mei said.

Neuregulin-1 is essential for heart development as well as formation of myelin, the insulation around nerves. It's among about 100 schizophrenia-associated genes identified through genome-wide association studies and has remained a consistent susceptibility gene using numerous other methods for examining the genetics of the disease. It's also implicated in cancer.

The researcher appeared in the journal Neuron.

Source-ANI