Navigation Links
Coral, human cells linked in death
Date:6/9/2014

SAN DIEGO (June 6, 2014) Humans and corals are about as different from one another as living creatures get, but a new finding reveals that in one important way, they are more similar than anyone ever realized.

A biologist at San Diego State University has discovered they share the same biomechanical pathway responsible for triggering cellular self-destruction. That might sound scary, but killing off defective cells is essential to keeping an organism healthy.

The finding will help biologists advance their understanding of the early evolution of multicellular life, conservationists better understand the plight of modern corals, and medical researchers develop new drugs to fight diseases like cancer.

Steven Quistad, a graduate student working in the laboratory of SDSU virologist Forest Rohwer, made the discovery earlier this year somewhat by accident. Like Rohwer, Quistad has spent most of his research career so far studying viruses. Rohwer leads SDSU's Viral Information Institute, one of the university's Areas of Excellence. The cross-disciplinary institute explores interactions between viruses and the biosphere in order to improve human and environmental health.

While analyzing the proteins of the coral Acropora digitifera and matching them against human proteins, he found a peculiar similarity: Both had receptor proteins that receive signals from another protein called tumor necrosis factor, or TNF.

Orderly death

When TNF proteins attach themselves to a cell's TNF receptors, the cell launches into an orderly self-destruct mode. The protein strands inside the cell break down and the cellular components are cordoned off and carried away to be recycled. The process, known as apoptosis, plays a crucial role in cellular health, allowing defective cells to destroy themselves before they can cause damage to the organism.

When Quistad looked more closely at the coral's genome, he noticed that it had genes that coded for not just one TNF receptor, but 40 of them. TNF comes in many different "flavors," and each one matches with a particular receptor. The coral Quistad investigated had 14 different flavors of TNF and more TNF receptors than any other known organism on the planet. Humans, by comparison, have 25 TNF receptors.

So what would happen if you took the human version of a TNF protein and exposed it to a coral's TNF receptors?

Quistad and his colleagues did just that and watched for the telltale signs of apoptosis. Under a microscope, they saw evidence that the coral cell was breaking down within 10 minutes of exposure to human TNF. A series of other cellular signals associated with apoptosis confirmed it: Human TNF sets into motion programmed cell death in corals.

Vice versa?

Next, Quistad and colleagues wondered if coral TNF proteins would trigger apoptosis in human cells. They coaxed E. coli bacteria to express the same TNF proteins produced by corals and exposed them to cultured human tissue. Sure enough, apoptosis occurred in the human cells. Quistad published these results today in the Proceedings of the National Academy of Sciences.

The findings suggest that the pathway by which TNF triggers apoptosis is old. Extremely old.

"The fact that it goes both ways means that these domains haven't changed in half a billion years," Quistad said. "Corals are actually much more similar to humans than we ever realized."

That's interesting from an evolutionary biology perspective, Quistad said, because approximately 542 million years ago, organized life took off in a very big way.

Known as the Cambrian Explosion, this period saw the emergence of the early ancestors of much of the life that exists today, including humans. No one really knows what set off the Cambrian Explosion, but it's possible the evolution of orderly, systematic cell death played a leading role.

"TNF-induced apoptosis could turn out to be one of the major sparks of the Cambrian Explosion," Quistad said.

Coral conservation

Unfortunately, after half a billion years of success, corals today aren't doing so well. The effects of climate change and ocean pollution are taking their toll on the atolls. A fatal stress response known as coral bleaching, whereby corals expel the bacteria that give them their vibrant colors, is decimating corals around the world. Previous studies have linked apoptosis to this process, and indeed, the corals to which Quistad exposed TNF eventually bleached out.

A better understanding of how TNF mediates apoptosis in coral might allow conservationists to identify more resilient species, and then reintroduce these hardier corals to places where coral loss is hurting the local ecosystem, Quistad said.

Preserving and learning from these corals is important for human health, too. Corals are wonderfully complex organisms, Quistad said, and we're only beginning to learn their secrets.

"Many people look at a coral and think it's just a slimy rock," he said. "They think, 'How can it be so complex at a molecular level when it looks so simple?'"

Quistad said that by studying corals' various flavors of TNF proteins and TNF receptors, researchers might uncover medical properties useful for killing specific kinds of renegade cells, such as cancer cells.

"We have a lot to learn from corals about our own immune system," he said.


'/>"/>

Contact: Beth Chee
bchee@mail.sdsu.edu
619-594-4563
San Diego State University
Source:Eurekalert  

Related biology news :

1. NOAA reports discovery of table coral, Acropora cytherea, off Oahu
2. No limits to human effects on clouds
3. Study reveals rats show regret, a cognitive behavior once thought to be uniquely human
4. Can mice mimic human breast cancer? MSU study says yes
5. First demonstration in human cells of chromosomal translocations that cause certain cancer
6. Tumor chromosomal translocations reproduced for the first time in human cells
7. Scientists capture most detailed images yet of humans tiny cellular machines
8. Domestication of dogs may explain mammoth kill sites and success of early modern humans
9. Amber discovery indicates Lyme disease is older than human race
10. Virtual Physiological Human Conference 2014
11. Brazilian researchers find human menstrual blood-derived cells feed embryonic stem cells
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Coral, human cells linked in death
(Date:1/25/2016)... SEATTLE , Jan. 25, 2016  Glencoe Software, ... biotech, pharma and publication industries, will provide the data ... Phenotypic Screening Centre (NPSC). ... Phenotypic analysis ... even whole organisms, allowing comparisons between states such as ...
(Date:1/20/2016)... 20, 2016   MedNet Solutions , an innovative ... of clinical research, is pleased to announce the attainment ... are the result of the company,s laser focus on ... , it,s comprehensive, easy-to-use and highly affordable cloud-based ... Key MedNet growth achievements in 2015 include: ...
(Date:1/13/2016)... 13, 2016 ... of the  "India Biometrics Authentication & ... (2015-2020)"  report to their offering.  ... announced the addition of the  "India ... Estimation & Forecast (2015-2020)"  report ...
Breaking Biology News(10 mins):
(Date:2/4/2016)... 4, 2016  CytoSorbents Corporation (NASDAQ: CTSO ... flagship CytoSorb® blood filter to treat deadly inflammation ... world, announced that CEO Dr. Phillip Chan ... Capital Group,s 2016 Disruptive Growth & Healthcare Conference, ... Conference Presentation Details: Where: Convene ...
(Date:2/4/2016)... , Feb. 4, 2016 ContraVir Pharmaceuticals, Inc. ... the development and commercialization of targeted antiviral therapies, announced ... Investor Conference 2016, to be held February 8-9, 2016, ... Group,s 2016 Disruptive Growth & Healthcare Conference, taking place ... 10-11, 2016. James Sapirstein , Chief Executive ...
(Date:2/4/2016)... ... 2016 , ... Franz Inc. , an early innovator ... been recognized As “ Best in Semantic Web Technology - USA & Leader ... it’s our priority to showcase prominent professionals who are excelling in their industry ...
(Date:2/3/2016)... Feb. 3, 2016   ViaCyte, Inc ., ... first pluripotent stem cell-derived islet replacement therapy for ... development, today announced that ViaCyte and Janssen Biotech, ... Johnson & Johnson, have agreed to consolidate the ... The agreement provides ViaCyte with an exclusive license ...
Breaking Biology Technology: