Navigation Links
Researchers reveal lung's unique innate immune system

For the first time, scientists have documented an organ-specific innate immune system. In research published in the April 18 edition of the journal Immunity, scientists at the University of California, San Diego (UCSD) School of Medicine outline the unique mechanism by which the lung shapes its defensive strategies against microbial invasion.

"This innate immune response is specific to the lung, and was probably designed to minimize collateral damage to lung tissue caused by unchecked inflammation," said Eyal Raz, M.D., Professor of Medicine at UCSD School of Medicine.

The body's respiratory tract is constantly exposed to inhaled particles or microorganisms. The alveola ?tiny air sacs in the lung where exchanges of gases between the respiratory and circulatory systems takes place ?are protected from invading microbes by the alveolar macrophage.

Macrophages are white blood cells involved in the inflammatory response throughout the body, cells normally on the alert for invaders to kill. Alveolar macrophages are unique among macrophages in the body, because their activation is inhibited by TGFb, a compound expressed in the lung by epithelial cells.

"Because the microenvironment of the alveola is a delicate one, it would be damaged if the macrophage immune system was in a constant battle-ready status," said Raz. "This could readily lead to the type of inflammation we see in autoimmune diseases of the lung such as asthma."

Therefore, the alveola possess a complex immune system in which the macrophage is repressed in its steady state, activated when called upon to fight invading microorganisms, and then re-repressed, in a circuit that is unique to this microenvironment.

"Dissecting this immune mechanism provides us with the knowledge of how we might prolong the activation status of alveolar macrophages. This knowledge could prove to be essential in combating any novel microbial agents that could infect the lower air ways, such as a new flu strain or bioterrorist agents," said Raz.

The researchers' data outlines a complex circuit in which the alveolar macrophages circumvent the inhibition by TGFb for brief period of time, in order perform their immune task. This is accomplished through regulation of TGFb activity by a set of cell surface receptors, proteins called integrins.

This regulation allows the alveolar macrophages to take on their "killer" function ?the ability of macrophages to engulf invading microorganisms ?but only for a very limited period of time. The mediating role of TGFb, briefly inactivated by the integrin, is then restored by one of the lung's own enzymes, the MMP9.

"Basically, the macrophages wake up for a while, but the system's own enzymes activate the inhibitor that puts them back to sleep," said Kenji Takabayshi, Ph.D., first author of the study.

Other contributors to this paper include Maripat Corr, Tomoko Hayashi, Vanessa Redecke, Lucinda Beck, and Donald Guiney of the Department of Medicine at UCSD School of Medicine; and Dean Sheppard, Lung Biology Center, University of California, San Francisco.


Source:University of California - San Diego

Related biology news :

1. Researchers discover way to make cells in the eye sensitive to light
2. Researchers find how protein allows insects to detect and respond to pheromones
3. Researchers Uncover Key Step In Manufacture of Memory Protein
4. Researchers reveal the infectious impact of salmon farms on wild salmon
5. Researchers identify target for cancer drugs
6. Researchers discover molecule that causes secondary stroke
7. Researchers find missing genes of ancient organism
8. Researchers trace evolution to relatively simple genetic changes
9. Researchers add new tool to tumor-treatment arsenal
10. UF Researchers Map Bacterial Proteins That Cause Tooth Loss
11. VCU Researchers Identify Networks Of Genes Responding To Alcohol In The Brain
Post Your Comments:

(Date:6/22/2016)... BETHESDA, Md. , June 22, 2016  The American ... by Trade Show Executive Magazine as one of ... Summit on May 25-27 at the Bellagio in ... based on the highest percentage of growth in each of ... number of exhibiting companies and number of attendees. The 2015 ...
(Date:6/20/2016)... Securus Technologies, a leading provider of ... safety, investigation, corrections and monitoring announced that after ... secured the final acceptance by all three (3) ... Systems (MAS) installed. Furthermore, Securus will have contracts ... by October, 2016. MAS distinguishes between legitimate wireless ...
(Date:6/9/2016)... , June 9, 2016 ... deploy Teleste,s video security solution to ensure the safety of ... during the major tournament Teleste, an ... systems and services, announced today that its video security solution ... to back up public safety across the country. The ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... , June 23, 2016 A person commits ... the crime scene to track the criminal down. ... U.S. Food and Drug Administration (FDA) uses DNA evidence to ... Sound far-fetched? It,s not. The FDA has ... to support investigations of foodborne illnesses. Put as simply as ...
(Date:6/23/2016)... --  EpiBiome , a precision microbiome engineering company, today ... from Silicon Valley Bank (SVB). The financing will allow ... drug development efforts, as well as purchase additional lab ... been an incredible strategic partner to us – one ... provide," said Dr. Aeron Tynes Hammack , EpiBiome,s ...
(Date:6/23/2016)... , June 23, 2016  Blueprint Bio, a company ... to the medical community, has closed its Series A ... Nunez . "We have received a commitment ... capital we need to meet our current goals," stated ... us the runway to complete validation on the current ...
(Date:6/23/2016)... ... June 23, 2016 , ... Velocity Products, ... tools designed, tuned and optimized exclusively for Okuma CNC machining centers at The ... of a collaboration among several companies with expertise in toolholding, cutting tools, machining ...
Breaking Biology Technology: