Features | Partner Sites | Information | LinkXpress
Sign In
Demo Company

Molecular Interactions Identified That Block Protein Transfer into Mitochondria of Huntington's Disease Neurons

By BiotechDaily International staff writers
Posted on 08 Jul 2014
Image: A microscope image of a neuron with inclusion (stained orange) caused by Huntington\'s disease (Photo courtesy of Wikimedia Commons).
Image: A microscope image of a neuron with inclusion (stained orange) caused by Huntington\'s disease (Photo courtesy of Wikimedia Commons).
Researchers have identified a protein complex that interacts with the mutated form of huntingtin protein to impair transport of proteins into the mitochondria of brain cells, which leads to their malfunction and the loss of neurons that characterizes Huntington's disease.

Huntington’s disease is caused by a dominant gene that encodes a protein known as huntingtin (Htt). The 5' end of the Huntington's disease gene has a sequence of three DNA bases, cytosine-adenine-guanine (CAG), coding for the amino acid glutamine, that is repeated multiple times. Normal persons have a CAG repeat count of between 7 and 35 repeats, while the mutated form of the gene has anywhere from 36 to 180 repeats. The mutant form of Htt is broken down into toxic peptides, which contribute to the pathology of the syndrome.

Investigators at the Washington University School of Medicine (St. Louis, MO, USA) and their colleagues at the University of Pittsburgh (PA, USA) worked with in vitro culture models and with a mouse model that mimicked the early stages of Huntington's disease.

They reported in the May 18, 2014, online edition of the journal Nature Neuroscience that recombinant mutant Htt directly inhibited mitochondrial protein import in their culture model. Furthermore, mitochondria from the brain synaptosomes of presymptomatic Huntington's disease model mice and from mutant Htt-expressing primary neurons exhibited a protein import defect, suggesting that deficient protein import was an early event in Huntington's disease.

At the molecular level, the investigators spotted interactions between mutant Htt and the TIM23 (translocase of inner mitochondrial membrane 23) mitochondrial protein import complex. Overexpression of TIM23 complex subunits attenuated the mutant Htt–induced mitochondrial import defect and subsequent neuronal death, which demonstrated that deficient mitochondrial protein import caused mutant Htt-induced neuronal death.

“We showed the problem could be fixed by making cells overproduce the proteins that make this transfer possible,” said first author Dr. Hiroko Yano, assistant professor of neurological surgery, neurology, and genetics at the Washington University School of Medicine. “We do not know if this will work in humans, but it is exciting to have a solid new lead on how this condition kills brain cells.”

Related Links:

Washington University School of Medicine
University of Pittsburgh 


Drug Discovery

view channel
Image: Endoscopic image of a bowel section known as the sigmoid colon afflicted with ulcerative colitis. The internal surface of the colon is blotchy and broken in places (Photo courtesy of Wikimedia Commons).

Orally Delivered Curcumin-Loaded Microparticles Effectively Treat Mouse Model of Ulcerative Colitis

Microparticles (MPs) loaded with the efficient anti-inflammatory agent curcumin were found to effectively treat a mouse model of ulcerative colitis. Ulcerative colitis is a chronic relapsing disease... Read more

Lab Technologies

view channel

New Genomic Research Kit Simplifies Exome Studies

An exciting new tool is now available for biotech researchers working in the field of genomic analysis. The human exome is critical to our genetic make-up and is generally accepted as having the greatest influence on how the genetic blueprint is utilized. The exome is defined as all coding exons in the genome and is... Read more


view channel

Collaboration Agreement to Boost Discovery of Fully Human Antibodies for Therapeutic Use

The discovery of fully human antibodies for therapeutic use will be boosted by a recently announced collaboration between a major university research center and a dynamic biopharmaceutical development company. Regeneron Pharmaceuticals, Inc. (Tarrytown, New York, USA) and The Experimental Therapeutics Institute (ETI)... Read more


17 Oct 2015 - 21 Oct 2015
25 Oct 2015 - 29 Oct 2015
16 Nov 2015 - 19 Nov 2015
Copyright © 2000-2015 Globetech Media. All rights reserved.