Navigation Links
When cells reach out and touch
Date:5/1/2009

MicroRNAs are single-stranded snippets that, not long ago, were given short shrift as genetic junk. Now that studies have shown they regulate genes involved in normal functioning as well as diseases such as cancer, everyone wants to know: What regulates microRNAs?

Scientists at Johns Hopkins were surprised to find an elegantly simple answer: touch. In a new study, published online April 9 in the Proceedings of the National Academy of Sciences, the researchers discovered that cell-to-cell contact revs up the manufacture of these small but mighty molecules.

"This study documents one of the very few clear examples of a stimulus that directly influences the global efficiency of microRNA production," says Josh Mendell, M.D., Ph.D., an assistant professor in the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine. "No one anticipated, including us, that the production of microRNAs is linked to how densely cells are packed together."

In what Mendell describes as an "accidental discovery," the team was studying contact inhibition: a phenomenon in which non-cancerous cells growing in a dish stop multiplying when they touch each other. Cancer cells, on the other hand, lose contact inhibition and continue to proliferate even when they're touching. The researchers suspected that microRNAs might play a role in contact inhibition because whenever they studied these enigmatic bits -- only about 20 or so genetic building blocks comprise a microRNA -- they always saw more in the tissues of animals, where cells are packed together, relative to the amount they found in isolated cells growing in culture.

To investigate, the team grew cancer cells and non-cancer cells to increasing densities in culture and, using a tool developed in the Mendell laboratory, measured the abundance of hundreds of microRNAs simultaneously. This analysis revealed that the more densely the cells were packed together, the more microRNA was produced in each cell.

The scientists then examined microRNA production in five additional commonly studied human and mouse cell lines, including human breast cancer cells, human colorectal cancer cells and human pancreatic cancer cells. They also tested fruit fly cells to determine whether or not the phenomenon is restricted to mammals.

In all tested cell lines, including the fruit fly cells, scientists observed a dramatic increase in microRNA abundance with increasing cell density.

"All evidence points to the fact that physical contact -- when cells actually touch each other -- is the critical factor that revs up the production of microRNAs," Mendell says. "Through additional experiments, we were able to identify the specific molecular steps at which microRNA production is affected. We expect that this phenomenon will profoundly influence how cells behave in normal development and disease."

The team's finding has practical importance for researchers who are investigating a range of biological processes that are most conveniently studied in cells growing in culture, Mendell says: "Little did we know the manufacture of microRNAs was so potently influenced simply by growing cells to different densities. We now recognize that this is a critical parameter that must be closely monitored when performing experiments with microRNAs in tissue culture."

A better understanding of how microRNA production is regulated is important because a reduction in the abundance of these molecules has been linked to the development of certain cancers. To date, one barrier to understanding how microRNAs are regulated in normal development and in disease states has been the lack of a simple system by which scientists could turn on and off a molecular pathway that controls microRNA production. Now, it seems, they may be able to toggle that pathway using cell-to-cell contact.

"If we can identify the mechanisms through which microRNA production is regulated in normal settings, such as under conditions of extensive cell-cell contact, we can then ask whether the same mechanisms block microRNA manufacture in diseases such as cancer," Mendell says. "This might allow the development of small molecules or other methods to turn microRNA production back on for therapeutic benefit."


'/>"/>

Contact: Maryalice Yakutchik
myakutc1@jhmi.edu
443-287-2251
Johns Hopkins Medical Institutions
Source:Eurekalert

Related biology news :

1. ESF EURYI award winner aims to stop cancer cells reading their own DNA
2. Newly created cancer stem cells could aid breast cancer research
3. AIDS interferes with stem cells in the brain
4. Clemson scientists shed light on molecules in living cells
5. Social habits of cells may hold key to fighting diseases
6. UF scientists reveal how dietary restriction cleans cells
7. Human derived stem cells can repair rat hearts damaged by heart attack
8. Scientists identify embryonic stem cells by appearance alone
9. Cells united against cancer
10. Pittsburgh scientists identify human source of stem cells with potential to repair muscle
11. U of M begins nations first clinical trial using T-reg cells from cord blood in leukemia treatment
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:11/29/2016)... Nearly one billion matches per second with DERMALOG,s high-speed AFIS    ... ... DERMALOG is Germany's largest Multi-Biometric supplier: The ... Identification Systems) ... Germany's largest Multi-Biometric supplier: The company's Fingerprint Identification System is part of ...
(Date:11/22/2016)... 2016 According to the new market research report ... Vein, Signature, Voice), Multi-Factor), Component (Hardware and Software), Function (Contact and Non-contact), ... market is expected to grow from USD 10.74 Billion in 2015 to ... 2016 and 2022. Continue Reading ... ...
(Date:11/19/2016)... 2016 Securus Technologies, a leading provider of ... investigation, corrections and monitoring, announced today that it has ... have an independent technology judge determine who has the ... tech/sophisticated telephone calling platform, and the best customer service. ... most of what we do – which clearly is ...
Breaking Biology News(10 mins):
(Date:12/8/2016)... ... December 08, 2016 , ... Opal Kelly, ... essential device-to-computer interconnect using USB or PCI Express, announced the FOMD-ACV-A4, the company's ... is a small, thin, SODIMM-style module that fits a standard 204-pin SODIMM socket ...
(Date:12/8/2016)... , Dec. 8, 2016  Anaconda BioMed S.L., a ... of the next generation neuro-thrombectomy system for the treatment ... Tudor G. Jovin, MD to join its Scientific Advisory ... a strategic network of scientific and clinical experts to ... of the ANCD BRAIN ® to its clinical ...
(Date:12/8/2016)... ... December 08, 2016 , ... Microbial genomics leader, uBiome, joins ... one of just six company finalists in the Health & Medicine category. Over ... nominated as finalists in this year’s awards include Google, SpaceX, Oculus, and SolarCity. ...
(Date:12/8/2016)... , Dec. 8, 2016 Soligenix, Inc. ... company focused on developing and commercializing products to treat ... announced today that it will be hosting an Investor ... ET on the origins of innate defense regulators (IDRs) ... review of oral mucositis and the recently announced and ...
Breaking Biology Technology: