Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers pinpoint sources of fibrosis-promoting cells that ravage organs

02.07.2013
4 pathways lead to creation of myofibroblasts that cause destructive runaway scarring

Scientists have tracked down and quantified the diverse origins of cells that drive fibrosis, the incurable, runaway wound-healing that scars and ultimately destroys organs such as the lungs, liver and kidneys.

Findings from research conducted at Beth Israel Deaconess Medical Center, Harvard Medical School and Massachusetts Institute of Technology in Boston and continued at The University of Texas MD Anderson Cancer Center are reported in an advance online publication at Nature Medicine on June 30.

"Answering a fundamental question about the origin of these cells by identifying four separate pathways involved in their formation allows us to look at ways to block those pathways to treat fibrosis," said senior author Raghu Kalluri, Ph.D., M.D., MD Anderson chair and professor of Cancer Biology. "It's highly unlikely that a single drug will work."

"In addition to being lethal in its own right, fibrosis is a precursor for the development of cancer and plays a role in progression, metastasis and treatment resistance," Kalluri said. "In some cancers, such as pancreatic cancer, up to 95 percent of tumors consist of fibrotic stroma."

Working in genetic mouse models of kidney fibrosis, Kalluri and colleagues identified four sources of cells called myofibroblasts, the dominant producers of collagen. Collagen normally connects damaged tissue and serves as scaffolding for wound-healing. As healing occurs, myofibroblasts and collagen usually diminish or disappear.

In fibrosis, collagen production marches on. While inflammation-inhibiting drugs can sometimes slow its progress, fibrosis now is treatable only by organ transplant.

Myofibroblasts have four types of parents

The researchers employed a fate-mapping strategy to track cells on their way to becoming myofibroblasts. In fate mapping, the promoter of a protein expresses a color inside a cell that remains with the cell no matter what happens to it until it dies, Kalluri said.

This was particularly important because two of the four sources of myofibroblasts start out as another cell type and differentiate into the collagen-producing cells.

Their experiments showed:

Half of all myofibroblasts are produced by the proliferation of pre-existing resting fibroblasts.

Another 35 percent are produced by mesenchymal stem cells that originate in the bone marrow, migrate to the "wound" site, and then differentiate into myofibroblasts.

An additional 10 percent are the products of endothelial to mesenchymal transition (EndMT), in which blood vessel cells change into mesenchymal cells, then become myofibroblasts.

The final 5 percent come from epithelial to mesenchymal transition (EMT), in which functional cells of an organ sometimes behave like mesenchymal cells and myofibroblasts.

"These differentiation pathways provide leads for drug targets," Kalluri said.
"Combining an antiproliferation drug with therapies that block one or more differentiation pathways could provide a double hit to control fibrosis. We hope to synergize these pathways for the most effective therapeutic response."

Recruitment from the bone marrow, EMT and EndMT appear to rely on transforming growth factor beta 1 (TGF-B1) to differentiate into myofibroblasts.

Pericytes are not involved

Some earlier descriptive studies implicated pericytes – connective, contractile cells that surround blood vessels – in the creation of myofibroblasts. The researchers tested pericytes via fate-mapping and found that they're not involved in myofibroblast generation.

Deleting pericytes did not improve kidney fibrosis or change the recruitment of myofibroblasts.

While their research focused on kidney fibrosis, the scientists believe their findings will be applicable to other types of fibrosis.

"Recruitment of fibroblasts is heterogonous. The sources are likely to be the same for lung or liver fibrosis, but the ratios may be different," Kalluri said. "Now we need to go into those other organs and establish a baseline of what we're facing like we did in kidney fibrosis."

Kalluri holds the Rebecca Meyer Brown and Joseph Mellinger Brown Chair in Basic Science Research and also and directs MD Anderson's Metastasis Research Center.

Co-authors with Kalluri are lead author Valeria LeBleu, Ph.D., and Hikaru Sugimoto, Ph.D., of MD Anderson's Department of Cancer Biology and Metastasis Research Center and formerly of the Department of Matrix Biology at Beth Israel Deaconess Medical Center, the home of co-authors Gangadhar Taduri, M.D., Joyce O'Connell, Ph.D.,Vesselina Cooke, Ph.D., and Craig Woda, M.D.

This research was funded by grants from the National Institutes of Health (DK55001, DK81976, CA125550, CA155370 and CA151925, 2T32DK007760-11, (5T32HL007374-30), the U.S. National Research Service Award F32 Ruth Kirschstein Postdoctoral Fellowship ((5F32DK082119-02) and the U.S. Department of Defense Breast Cancer Predoctoral Traineeship Award.

Scott Merville | EurekAlert!
Further information:
http://www.mdanderson.org

More articles from Health and Medicine:

nachricht Routing gene therapy directly into the brain
07.12.2017 | Boston Children's Hospital

nachricht New Hope for Cancer Therapies: Targeted Monitoring may help Improve Tumor Treatment
01.12.2017 | Berliner Institut für Gesundheitsforschung / Berlin Institute of Health (BIH)

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Midwife and signpost for photons

11.12.2017 | Physics and Astronomy

How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas

11.12.2017 | Earth Sciences

PhoxTroT: Optical Interconnect Technologies Revolutionized Data Centers and HPC Systems

11.12.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>