Featured Research

from universities, journals, and other organizations

Breaking bad mitochondria: How hepatitis C survives for so long

Date:
April 15, 2014
Source:
University of California, San Diego Health Sciences
Summary:
A mechanism has been discovered that explains why people with the hepatitis C virus get liver disease and why the virus is able to persist in the body for so long. The hard-to-kill pathogen, which infects an estimated 200 million people worldwide, attacks the liver cells' energy centers -- the mitochondria -- dismantling the cell's innate ability to fight infection. It does this by altering cells mitochondrial dynamics.

Mitochondria in hepatitis C-infected cells (bottom row) are self-destructing. The self-annihilation process explains the persistance and virulence of the virus in human liver cells.
Credit: UC San Diego School of Medicine

Researchers at the University of California, San Diego School of Medicine have identified a mechanism that explains why people with the hepatitis C virus get liver disease and why the virus is able to persist in the body for so long.

Related Articles


The hard-to-kill pathogen, which infects an estimated 200 million people worldwide, attacks the liver cells' energy centers -- the mitochondria -- dismantling the cell's innate ability to fight infection. It does this by altering cells mitochondrial dynamics.

The study, published in today's issue of the Proceedings of the National Academy of Sciences, suggests that mitochondrial operations could be a therapeutic target against hepatitis C, the leading cause of liver transplants and a major cause of liver cancer in the U.S.

"Our study tells us the story of how the hepatitis C virus causes liver disease," said Aleem Siddiqui, PhD, professor of medicine and senior author. "The virus damages mitochondria in liver cells. Cells recognize the damage and respond to it by recruiting proteins that tell the mitochondria to eliminate the damaged area, but the repair process ends up helping the virus."

Mitochondria are organelles in a cell that convert energy from food (glucose) into a form of energy that can be used by cells called adenosine triphosphate.

Specifically, the researchers discovered that the virus stimulates the production of a protein (Drp 1) that induces viral-damaged mitochondria to undergo asymmetric fragmentation. This fragmentation (fission) results in the formation of one healthy mitochondrion and one damaged or bad mitochondrion, the latter of which is quickly broken down (catabolized) and dissolved in the cell's cytoplasm.

Although the fragmentation serves to excise the damaged area from the mitochondrion, the formation of a healthy mitochondrion also helps keep the virus-infected cell alive. Moreover, the virus is able to use the mitochondrial remains (all the amino acids and lipids from the catabolized mitochondrion) to help fuel its continued replication and virulence.

"It's like the bad part of the house is demolished to the benefit of the virus," Siddiqui said.

In their experiments, the researchers showed that hepatitis C-infected cells with higher Drp 1 protein levels also produced less interferon, the body's natural immune booster. These cells were also less likely to undergo apoptosis, a process that would encourage damaged cells to essentially kill themselves.

The reverse was also observed: When the Drp 1 protein was "silenced," interferon production and apoptotic activity increased.

"Mitochondrial processes are at the center of understanding the persistence of the virus and how it flies under the radar of the body's natural immune response," he said. "The trick is to find a way to deliver a drug that could target the Drp 1 protein specifically in hepatitis C-infected liver cells, maybe through nanotechnology."


Story Source:

The above story is based on materials provided by University of California, San Diego Health Sciences. Note: Materials may be edited for content and length.


Journal Reference:

  1. S.-J. Kim, G. H. Syed, M. Khan, W.-W. Chiu, M. A. Sohail, R. G. Gish, A. Siddiqui. Hepatitis C virus triggers mitochondrial fission and attenuates apoptosis to promote viral persistence. Proceedings of the National Academy of Sciences, 2014; DOI: 10.1073/pnas.1321114111

Cite This Page:

University of California, San Diego Health Sciences. "Breaking bad mitochondria: How hepatitis C survives for so long." ScienceDaily. ScienceDaily, 15 April 2014. <www.sciencedaily.com/releases/2014/04/140415143959.htm>.
University of California, San Diego Health Sciences. (2014, April 15). Breaking bad mitochondria: How hepatitis C survives for so long. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2014/04/140415143959.htm
University of California, San Diego Health Sciences. "Breaking bad mitochondria: How hepatitis C survives for so long." ScienceDaily. www.sciencedaily.com/releases/2014/04/140415143959.htm (accessed October 25, 2014).

Share This



More Health & Medicine News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
WHO: Millions of Ebola Vaccine Doses by 2015

WHO: Millions of Ebola Vaccine Doses by 2015

AP (Oct. 24, 2014) The World Health Organization said on Friday that millions of doses of two experimental Ebola vaccines could be ready for use in 2015 and five more experimental vaccines would start being tested in March. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Doctor in NYC Quarantined With Ebola

Doctor in NYC Quarantined With Ebola

AP (Oct. 24, 2014) An emergency room doctor who recently returned to the city after treating Ebola patients in West Africa has tested positive for the virus. He's quarantined in a hospital. (Oct. 24) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins