Navigation Links
Blood pressure enzyme can have tumor-sensing role

By increasing production of a blood pressure-regulating enzyme in mice, researchers have found they can enhance the mouse immune system's ability to sense tumor growth.

When scientists at Emory University School of Medicine engineered mice that make more angiotensin-converting enzyme in white blood cells called macrophages, the mice could more effectively limit the growth of injected tumors.

The enzyme works by "trimming" small bits of protein that originate from the tumors, allowing the immune system to identify the tumors and mount a response more efficiently.

The results are published online in the Journal of Biological Chemistry (JBC).

Senior author Kenneth Bernstein, MD, Emory distinguished service professor of pathology and laboratory medicine, says his group's findings suggest a strategy for amplifying immune system function in humans.

"We think we've discovered a means of tweaking the immune response by modifying the process of antigen presentation," Dr. Bernstein says.

In the clinic, doctors might be able to enhance a cancer patient's ability to resist a tumor by removing his or her white blood cells, boosting their production of angiotensin-converting enzyme, and re-infusing them, he says.

Antigen presentation refers to how proteins from within the body are constantly recycled and chewed up into small bits called peptides, which appear on the surfaces of cells. While the immune system generally ignores peptides from proteins in the body, it can respond to the peptides from foreign invaders.

Angiotensin-converting enzyme, or ACE, plays a critical role in controlling blood pressure and is the target of common medications. The hormone angiotensin (a peptide) constricts blood vessels, increases the brain's perception of thirst and indirectly causes the kidneys to retain sodium, thus limiting its production can reduce blood pressure.

ACE acts chemically by removing amino acids, the building blocks of proteins, from one end of a larger protein. In the body, ACE converts an inactive form of angiotensin into an active form by clipping off two amino acids.

But angiotensin is not ACE's only target. In previous studies, Bernstein and his co-workers found that manipulating its activity also affects processes such as fertility and the generation of red blood cells in the bone marrow.

To dissect out ACE's role in the immune system, they created mice with a genetic alteration in the ACE gene, forcing the gene to be turned on only in macrophages.

Macrophages are especially good at displaying peptides on their surfaces to other white blood cells called T cells so that the T cells are stimulated to grow. The T cells in turn kill virally infected cells. Depending on the situation, they can sometimes kill tumor cells as well.

When injected with several types of melanoma or lymphoma, the altered mice developed smaller tumors than normal mice. The tumors they did have contained more white blood cells attacking the cancerous cells.

In the JBC paper, the researchers show that ACE boosts cells' ability to display some foreign peptides, increasing their ability to stimulate T cells by several-fold.

Bernstein cautions that normally, macrophages make little ACE, so its effects must be seen as artificial. He notes that ACE inhibitors such as enalapril and lisinopril are taken by millions of people with high blood pressure and have not been reported to weaken the immune system.

However, cells similar to macrophages have been shown to produce ACE in response to pathogens such as sarcoid or leprosy, he says.


Contact: Holly Korschun
Emory University

Related medicine news :

1. Specific antagonism lowers blood pressure
2. Restricting Blood Flow May Help Heart Bypass Patients
3. FDA Updates Prescription Guidelines for Blood Thinner
4. Doctors Often Miss High Blood Pressure in Kids
5. Back to School Means Return of School Blood Drives
6. Blood-flow detector software show promise in preventing brain damage
7. FDA Approves New Roche West Nile Virus Blood Screening Test
8. Australian-led international study shows blood pressure drugs cut death rate in type 2 diabetes
9. Laser blasts viruses in blood
10. Study Demonstrates Marteks Algal DHA Oil Improves Blood Triglyceride Lipid Levels
11. LifeMasters Provides Tips for Maintaining a Healthy Blood Cholesterol Level
Post Your Comments:
(Date:11/25/2015)... ... November 25, 2015 , ... In an ongoing Clinical ... Center (RMC) in Chicago, IL, UV Angel is evaluating the efficacy of its product ... intensive care units (totaling 30 beds) from May 2014 through October 2015 at a ...
(Date:11/25/2015)... ... November 25, 2015 , ... In ... nation’s Periwinkle Pioneers, individuals and groups responsible for advancing care for pulmonary hypertension ... Pioneers, nominated by the public, will receive special recognition throughout 2016 as part ...
(Date:11/25/2015)... ... ... Many people know of the common symptoms of low thyroid hormone (also ... many people who find their cholesterol levels and weight are creeping up are more ... they don’t have any of the other symptoms. , Thyroid hormone plays a major ...
(Date:11/25/2015)... ... November 25, 2015 , ... ... lower prices in an early celebration of the early holiday shopping season. Starting ... $29.95 each (normally $33.95 ea). Black Friday promotional pricing is in addition to ...
(Date:11/24/2015)... Mississauga, ON (PRWEB) , ... November 24, 2015 , ... ... Deborah Williams without a referral for dental implants at her Mississauga, ON ... qualified and experienced in the placement of dental implants. , Missing teeth can ...
Breaking Medicine News(10 mins):
(Date:11/25/2015)... LYON , Frankreich, November 25, 2015 ... hat heute bekanntgegeben, dass sie eine Lizenz für das ... Inserm, Poxel, CNRS, UCBL und ENS-Lyon innehaben, an Enyo ... 2009 von FUI AAP8 ins Leben gerufenen und von ... NATHEB-Programms wurde FXR als ein Behandlungsziel für HBV identifiziert, ...
(Date:11/24/2015)... Nov. 24, 2015  Natera, Inc. (Nasdaq: ... genetic testing and the analysis of circulating ... present at the 27 th  Annual Piper ... 2015 at 1:00 p.m. ET.  Matthew Rabinowitz, Ph.D., CEO of ... business activities and financial outlook. ...
(Date:11/24/2015)... , 24. November 2015 Avery ... Pacemaker Systems, ist erfreut, die Berufung von ... bekannt geben zu können. ... --> Foto - ... (Schweden). Von 1984-1986 war er Fellow des ...
Breaking Medicine Technology: