Navigation Links
Red blood cells have a tiny but effective protector -- microRNA
Date:7/31/2010

Pediatric researchers have discovered a new biological pathway in which small segments of RNA, called microRNA, help protect red blood cells from injury caused by chemicals called free radicals. The microRNA seems to have only a modest role when red blood cells experience normal conditions, but steps into action when the cells are threatened by oxidant stress.

Led by hematologist Mitchell Weiss, M.D., Ph.D., of The Children's Hospital of Philadelphia, the current study describes how a particular microRNA fine-tunes gene activity by acting on an unexpected signaling pathway.

The study appears in the August 1 issue of the journal Genes & Development, simultaneously with a similar study of microRNAs and red blood cells by a University of Texas team led by Eric Olson, Ph.D. The two studies reinforce each other, said Weiss.

MicroRNAs are single-stranded molecules of ribonucleic acid (RNA) averaging only 22 nucleotides long. Scientists estimate that 500 to 1000 microRNAs exist in the human genome. First characterized in the early 1990s, they received their current name in 2001. Over the past decade, scientists have increasingly recognized that microRNAs play a crucial role in regulating genes, most typically by attaching to a piece of messenger RNA and blocking it from being translated into a protein, but many details remain to be discovered.

"Although microRNAs affect the formation and function of most or all tissues, for most microRNAs, we don't know their precise mechanisms of action," said Weiss. "In this case we already knew this microRNA, called miR-451, regulates red blood cells in zebrafish and mice, and because it is highly conserved in evolution, we presume it operates in humans as well. But its functional roles were poorly understood."

By investigating how microRNAs influence red blood cell development, Weiss and colleagues aimed to understand how such development goes wrong in hemolytic anemia, in which red blood cells are destroyed in large numbers, or in disorders of abnormal blood cell production. The current study used knockout micebioengineered animals in which the miR-451 gene was removed and could not function.

They found that preventing the activity of miR-451 produced only modest effectsmild anemia in the micebut when the team subjected mice to oxidant stress by dosing them with a drug that produces free radicals, the mice had profound anemia. The oxygen radicals attacked hemoglobin, the iron-carrying molecule in red blood cells.

"This is a common theme in microRNAsfrequently, they don't play a central role during tissue formation or normal conditions, but they have a strong protective effect when an organism is stressed," said Weiss. "Over evolutionary time, red blood cells have evolved ways to protect themselves; one of those ways is the action of microRNA."

Weiss's team found that miR-451, acting through intermediate steps on a signaling pathway, affects a key protein, FoxO3. As a transcription factor, FoxO3 regulates hundreds of genes; in this case, FoxO3 stimulates specific genes that protect red blood cells from oxidant stress. The knockout mice in this study, having lost miR-451's function, showed impaired FoxO3 activity, and less ability to protect their red blood cells.

The regulatory pathway seen here, Weiss added, may have medical implications beyond blood cell development. "This finding does not have immediate clinical application for patients with blood diseases, but it sheds light on how microRNAs fine tune physiological functions in different contexts," said Weiss. FoxO3 regulates anti-oxidant functions in heart cells and also acts as a tumor suppressor, so miR-451 may have an important role in heart protection and in fighting cancers. "Further studies may broaden our knowledge of how this microRNA may defend the body against disease," he added.


'/>"/>

Contact: John Ascenzi
Ascenzi@email.chop.edu
267-426-6055
Children's Hospital of Philadelphia
Source:Eurekalert

Related biology news :

1. Rare and common genetic variations responsible for high triglyceride levels in blood
2. Noninvasive MR imaging of blood vessel growth in tumors using nanosized contrast agents
3. UT MD Anderson study ties abnormal cells in blood to lung cancer
4. Adaptation in mole blood aids tunnelling
5. Toward making extended blood group typing more widely available
6. Pitt researchers find new proteins that regulate blood pressure, flow
7. For lambs, a pasture a week keeps blood suckers away
8. Waters unexpected role in blood pressure control
9. Reprogrammed human blood cells show promise for disease research
10. Cheap, simple, noninvasive blood test may replace invasive diagnostic techniques in early pregnancy
11. Dark chocolate lowers blood pressure
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/2/2017)... YORK , March 2, 2017 Summary ... better understand Perrigo and its partnering interests and activities since ... ... Partnering Deals and Alliance since 2010 report provides an in-depth ... leading life sciences companies. On demand company reports ...
(Date:3/2/2017)... 2, 2017 Australian stem cell and regenerative ... has signed an agreement with the Monash Lung Biology ... Discovery Institute and Department of Pharmacology at Monash University, ... preclinical study to support the use of Cymerus™ mesenchymal ... Asthma is a chronic, long term lung ...
(Date:2/28/2017)... February 28, 2017 News solutions for biometrics, ... ... from 14 to 16 March, Materna will present its ... how seamless travel is a real benefit for passengers. To ... to their passenger touch point solutions to take passengers through the ...
Breaking Biology News(10 mins):
(Date:3/23/2017)... Colo. , March 23, 2017  GlobeImmune, Inc. ... agreement for the sale of 12,835,490 shares of its ... NantWorks  ecosystem of companies. In connection with the sale of ... $100,000 in cash and issue to GlobeImmune 200,000 shares, ... stock. "We are pleased to enter ...
(Date:3/23/2017)... , March 23, 2017 NetworkNewsWire Editorial ... ... putting significant strain on health care systems, in terms of ... rises, so too does the development of innovative and efficient ... effects. Among the many types of cancer treatments, a growing ...
(Date:3/23/2017)... ... March 23, 2017 , ... Advanced Polymer ... hire of Dr. Sigmund “Sig” Floyd as Vice President ? Global Business Development. ... development activities. , “Dr. Floyd’s career has spanned 30 years in the chemicals ...
(Date:3/22/2017)... Calif. , March 22, 2017  UBM ... proud to announce their extended partnership and the ... be headlined by the 21 st Annual ... Boston, taking place May 3-4, 2017. ... Medical Technology Association (ADVAMED) President and CEO, ...
Breaking Biology Technology: