Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Breaking bad mitochondria


Mechanism helps explain persistence of hepatitis C virus

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.

Hep C Mitochondria

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

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."


Co-authors include Seong-Jun Kim and Gulam H. Syed, Mohsin Khan and Wei-Wei Chiu Division of Infectious Diseases, UCSD; Muhammad A. Sohail, Division of Gastroenterology, UCSD; and Robert G. Gish, Hepatitis B Foundation.

This research was funded, in part, by National Institutes of Health grants AI085087, DK077704, DK08379 and T32 DK07202.

Scott LaFee | Eurek Alert!
Further information:

Further reports about: Cells Division Gastroenterology Hepatitis Medicine UCSD amino energy healthy liver mitochondrial protein proteins repair

More articles from Life Sciences:

nachricht International team discovers novel Alzheimer's disease risk gene among Icelanders
24.10.2016 | Baylor College of Medicine

nachricht New bacteria groups, and stunning diversity, discovered underground
24.10.2016 | DOE/Lawrence Berkeley National Laboratory

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

New method increases energy density in lithium batteries

24.10.2016 | Power and Electrical Engineering

International team discovers novel Alzheimer's disease risk gene among Icelanders

24.10.2016 | Life Sciences

New bacteria groups, and stunning diversity, discovered underground

24.10.2016 | Life Sciences

More VideoLinks >>>