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:5/23/2016)... ... May 23, 2016 , ... ... and sexual objectification, according to Georgia State University researchers. , In ... in the fifth, sixth and seventh grades shared their experiences with strained ...
(Date:5/23/2016)... ... May 23, 2016 , ... Cosmetic Town, an ... about cosmetic procedures, began updating their library of over 300 encyclopedic medical articles. ... articles in order to feature the latest breakthroughs in plastic surgery procedures since ...
(Date:5/23/2016)... WASHINGTON, D.C. (PRWEB) , ... May 23, 2016 , ... ... Phyllis Greenberger, MSW, has decided to move on from that role. , “No one ... years as did Phyllis Greenberger,” said SWHR Founder Florence Haseltine, MD, PhD. “We offer ...
(Date:5/23/2016)... ... 2016 , ... In Pursuit of Balance (IPOB) co-founders Jasmine Hirsch and Rajat ... the end of 2016. , “We created IPOB to change the dialogue around ... back on what we have achieved, we’re gratified by the response of wine producers, ...
(Date:5/23/2016)... ... May 23, 2016 , ... Four Circles Recovery Center, a ... is proud to announce the launch of its new extended care program, Fifth Circle. ... treatment at Four Circles or another primary treatment program, Fifth Circle is designed to ...
Breaking Medicine News(10 mins):
(Date:5/19/2016)... SAN FRANCISCO, Calif. , May 19, 2016 /PRNewswire/ ... a biopharmaceutical company developing novel therapeutics for the treatment ... announced that new GBT440 data will be presented in ... 21 st Congress in Copenhagen ... ongoing Phase 1/2 GBT440-001 study in sickle cell disease ...
(Date:5/19/2016)... 2016 BioLineRx Ltd. (NASDAQ/TASE: BLRX) ... treatment of multiple cancer and hematological indications, will be ... abstract titled " Clinical response in relapsed/refractory AML patients ... BL-8040, a potent CXCR4 antagonist; results of a Phase ... at the European Hematology Association 21st Congress, to be ...
(Date:5/19/2016)... CAMBRIDGE, Massachusetts , May 19, 2016 ... pharmaceuticals and diagnostics based on the gut microbiome, is pleased ... Cambridge, MA to support its operations ... office is located at Kendall Square, the heart of ... global hub for transforming scientific insights into new drugs. The ...
Breaking Medicine Technology: