Navigation Links
Getting rid of old mitochondria
Date:6/16/2014

It's broadly assumed that cells degrade and recycle their own old or damaged organelles, but researchers at University of California, San Diego School of Medicine, The Johns Hopkins University School of Medicine and Kennedy Krieger Institute have discovered that some neurons transfer unwanted mitochondria the tiny power plants inside cells to supporting glial cells called astrocytes for disposal.

The findings, published in the June 17 online Early Edition of PNAS, suggest some basic biology may need revising, but they also have potential implications for improving the understanding and treatment of many neurodegenerative and metabolic disorders.

"It does call into question the conventional assumption that cells necessarily degrade their own organelles. We don't yet know how generalized this process is throughout the brain, but our work suggests it's probably widespread," said Mark H. Ellisman, PhD, Distinguished Professor of Neurosciences, director of the National Center for Microscopy and Imaging Research (NCMIR) at UC San Diego and co-senior author of the study with Nicholas Marsh-Armstrong, PhD, in the Department of Neuroscience at Johns Hopkins University and the Hugo W. Moser Research Institute at Kennedy Krieger Institute in Baltimore.

"The discovery of a standard process for transfer of trash from neuron to glia will most likely be very important to understanding age-related declines in function of the brain and neurodegenerative or metabolic disorders," Marsh-Armstrong said. "We expect the impact to be significant in other areas of biomedicine as well."

The researchers looked specifically at the axons of retinal ganglion cells in mice, a type of neuron that transmits visual information from the eye to the brain. The investigation was prompted by observations by Marsh-Armstrong while studying a mouse model of glaucoma that protein products from the retina were accumulating in the optic nerve head (ONH) just behind the eye.

Using a combination of advanced microscopy and molecular techniques developed at the Ellisman and Marsh-Armstrong laboratories, they discovered that damaged mitochondria in retinal ganglion cells were shed at the ONH where ganglion cell axons exit the eye to form the optic nerve leading to the brain. These mitochondria were taken up and degraded by adjacent astrocytes, the most abundant form of glial cell in the vertebrate nervous system and the only cell which bridges between nerve cells and the brain's blood supply.

The discovery refutes the common assumption that all cells internally isolate, degrade and remove damaged materials a process generally known as autophagy (Greek for "to self-eat"). When the process involves mitochondria, it's called mitophagy. The process described by Marsh-Armstrong, Ellisman and colleagues has been dubbed "transmitophagy."

The surprising findings still leave questions to be answered. For example, do the mitochondria removed at the ONH originate only from the population residing in the long conducting nerve fibers from the eye to the brain or are some actively transported from the retina itself?

Ellisman said the findings could potentially improve understanding and perhaps eventually the treatment of diverse disorders. "Mitochondria play prominent roles in the health of axons, which are fundamental to connecting neurons and transmitting information. It should be a priority to further explore what happens in transmitophagy and whether defects in this phenomenon contribute to neuronal dysfunction or disease."


'/>"/>

Contact: Scott LaFee
slafee@ucsd.edu
619-543-6163
University of California - San Diego
Source:Eurekalert  

Related medicine news :

1. Study: Women not getting enough exercise; at risk of developing metabolic syndrome
2. HPV vaccine completion rate among girls is poor, getting worse
3. American Kids Getting Fewer Prescription Drugs: Study
4. Getting your message across
5. Cholesterol Levels Getting Better for U.S. Kids: CDC
6. Kids need at least 7 minutes a day of vigorous physical activity, but most arent getting that
7. U.S. Kids Getting Enough Sleep After All: Survey
8. Fitquip: Getting Fit for Christmas on the Beach
9. New Blog Post from iHealthology.com Announces Why Staying Fit Means Getting on the Move
10. Quorn Foods Inc. Releases a Statement Following an Article on Getting the Most Out of a Vegetarian Healthy Food Diet
11. People with diabetes in Ontario getting fewer government-funded eye exams, new study finds
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Getting rid of old mitochondria
(Date:6/24/2016)... ... 24, 2016 , ... Marcy was in a crisis. Her son James, eight, was out of ... verbally and physically. , “When something upset him, he couldn’t control his emotions,” remembers Marcy. ... throw rocks at my other children and say he was going to kill them. ...
(Date:6/24/2016)... ... 2016 , ... Global law firm Greenberg Traurig, P.A. announced that 20 Florida ... their peers for this recognition are considered among the top 2 percent of lawyers ... as members of this year’s Legal Elite Hall of Fame: Miami Shareholders Mark ...
(Date:6/24/2016)... ... June 24, 2016 , ... Comfort Keepers® of San ... Society and the Road To Recovery® program to drive cancer patients to and from ... adults to ensure the highest quality of life and ongoing independence. Getting to ...
(Date:6/24/2016)... ... ... People across the U.S. are sharpening their pencils and honing their writing skills ... patients and their families pay tribute to a genetic counselor by nominating him or ... Counselors (NSGC) Annual Education Conference (AEC) this September. , In April, Genome magazine ...
(Date:6/24/2016)... New York, NY (PRWEB) , ... June 24, ... ... lifestyle publication Haute Living, is proud to recognize Dr. Barry M. Weintraub as ... believes that “the most beautiful women in the world, and the most handsome ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... Bracket , a leading clinical trial technology ... outcomes platform, Bracket eCOA (SM) 6.0, at the 52 ... 30, 2016 in Philadelphia , Pennsylvania.  A ... product of its kind to fully integrate with RTSM, will ... 6.0 is a flexible platform for electronic clinical outcomes assessments ...
(Date:6/23/2016)... RIDGE, Ill. and INDIANAPOLIS ... of students receiving a Lilly Diabetes Tomorrow,s Leaders Scholarship ... The 2016 scholarship winners, announced today online at ... to let type 1 diabetes stand in the way ... Diabetes has supported the Foundation,s scholarship program since 2012, ...
(Date:6/23/2016)... 23, 2016 Revolutionary technology includes ... Oticon , industry leaders in advanced audiology and hearing ... Oticon Opn ™, the world,s first internet connected hearing ... IoT devices.      (Photo: http://photos.prnewswire.com/prnh/20160622/382240 ... number of ,world firsts,: , TwinLink™ - ...
Breaking Medicine Technology: