A Smart + Strong Site
Subscribe to:
E-newsletters
POZ magazine
JOIN AIDSMEDS YouTube

Back to home » Treatment News » Top Stories

Most Popular Stories
Undetectable Viral Load Essentially Eliminates Transmission Risk in Straight Couples
A 15-Year Jump in Life Expectancy for People With HIV
Life Expectancy for Young People With HIV Is Nearly Normal
Failure to Awaken Dormant Cells Deals Blow to HIV Cure Research
Scientists Devise Method of Snipping HIV From Immune Cells
Media Cooks Up Claim That Soy Sauce Treats, Even Cures HIV
FDA Approves New Single-Tablet HIV Regimen, Triumeq
What's That Mean?
(just double-click it!)

If you don't understand one of the words in this article, just double-click it. A window will open with a definition from mondofacto's On-line Medical Dictionary. If the double-click feature doesn't work in your browser, you can enter the word below:

Most Popular Lessons
Aging & HIV
The HIV Life Cycle
Shingles
Herpes Simplex Virus
Syphilis & Neurosyphilis
Treatments for Opportunistic Infections (OIs)
What is AIDS & HIV?
More News

Have medical or treatment news about HIV? Send press releases, news tips and other announcements to news@aidsmeds.com.

Click here for more news


emailprint

February 27, 2012

Possible Cure in Protein That Starves HIV of Needed Building Blocks

Focusing on a protein called SAMHD1, a team of researchers believes it has stumbled upon the mechanism in which some immune system cells keep HIV from hijacking their cellular machinery to produce new virus. The findings, published online ahead of print by the journal Nature Immunology, pave the way for novel methods to treat—and potentially cure—HIV infection.

SAMHD1, the international team of scientists explains, is found in white blood cells known as macrophages and related cells known as dendritic cells. Building upon research published last year, demonstrating that SAMHD1 makes it difficult for HIV to infect macrophages, the scientists have helped close the knowledge gap with the discovery that the protein cuts off the supply line of deoxyribonucleotide triphosphate (dNTP)—the building blocks of DNA—which HIV needs to re-create its genetic contents.

When a virus, like HIV, infects a cell, it hijacks the cell’s dNTP. Once the virus replicates, the resulting DNA molecule contains all the genes of the virus and instructs the cell to make more virus.

SAMHD1, the researchers found, protects the cell from viruses by destroying the pool of dNTPs, leaving the virus without any building blocks to make its genetic information, a process known as nucleotide pool depletion.

“SAMHD1 essentially starves the virus,” explained Nathaniel Landau, PhD, a professor of microbiology at New York University School of Medicine and a lead author of the Nature Immunology paper in an accompanying news announcement. “The virus enters the cell, and then nothing happens. It has nothing to build and replicate with, so no DNA is made.”

As a result, the most common form of HIV—HIV-1—does not readily infect these cells. Instead, the virus has evolved to replicate mainly in CD4 cells, which do not contain SAMHD1 and therefore have a healthy pool of dNTPs.

The virus, the researchers suggest, may have evolved in such a way that it deliberately avoids trying to infect immune cells that have SAMHD1, in order to avoid alerting the greater immune system to activate a variety of antiviral mechanisms to attack the virus.

The team also discovered how a protein in the other form of HIV—HIV-2, which is found mainly in Africa—knocks out SAMHD1. They found that the protein Vpx destroys SAMHD1, clearing the way for HIV-2 to infect macrophages. While scientists have known that HIV-2 needs Vpx to infect macrophages, they hadn’t known precisely why.

Interestingly, while one might think that a virus that is able to replicate itself in crucial cells like macrophages might be more dangerous than one that cannot, that’s not the case with HIV. The researchers note that HIV-2 is generally actually less virulent than HIV-1.

One possible explanation for this is that, like a starving man who becomes increasingly desperate for food, HIV-2—when faced with a shortage of raw materials—puts its mutation capabilities into overdrive, creating the Vpx proteins necessary to circumvent the pathway blocked by SAMHD1.

“Viruses are remarkably clever about evading our immune defenses,” Landau said. “They can evolve quickly and have developed ways to get around the systems we naturally have in place to protect us. It’s a bit of evolutionary warfare, and the viruses, unfortunately, usually win. We want to understand how the enemy fights so that we can outsmart it in the end.”

Understanding the mechanism by which SAMHD1 protects cells may provide a new idea about how to stop or slow the virus’s ability to spread, the researchers explained. Potential future research efforts, for example, might focus on finding a way to increase the amount of SAMHD1 in cells where it does not exist, such as CD4 cells, or to reduce the amount of dNTPs in cells vulnerable to infection.

This could potentially force HIV to remain dormant in all immune system cell lines, unable to replicate—another functional cure strategy.

“Over the past few years, a number of these natural resistance mechanisms have been identified, specifically in HIV,” Landau sad. “This is a very exciting time in HIV research. Many of the virus’s secrets are being revealed through molecular biology, and we’re learning a tremendous amount about how our immune system works through the study of HIV.”

Search: SAMHD1, deoxyribonucleotide triphosphate, dNTP, macrophages, dendritic cells


Scroll down to comment on this story.



Name:

(will display; 2-50 characters)

Email:

(will NOT display)

City:

(will display; optional)

Comment (500 characters left):

(Note: The AIDSmeds team reviews all comments before they are posted. Please do not include ":" "@" "<" ">" in your comment. The opinions expressed by people providing comments are theirs alone. They do not necessarily reflect the opinions of Smart + Strong, which is not responsible for the accuracy of any of the information supplied by people providing comments.)

Comments require captcha.
Please enter this number for verification:

| Posting Rules



Show comments (7 total)


[Go to top]

Quick Links
AIDSmeds en Español
About HIV and AIDS
Lab Tests
Clinical Trials
HIV Meds
Starting Treatment
Switching Treatment
Drug Resistance
Side Effects
Disclosure
Lipodystrophy
Hepatitis & HIV
Women & Children
Fact Sheets
Treatment News
Community Forums
Blogs
Conference Coverage
Health Services Directory
POZ Magazine


    dambitious
    Gone
    New York


    oceanblue65
    louisiana
    Louisiana


    latinpozdallas
    Dallas
    Texas


    robert12
    Queens
    New York
Click here to join POZ Personals!
Conference Coverage

XX International AIDS Conference
(AIDS 2014)
Melbourne, Australia
July 20 - 25, 2014


21st Conference on Retroviruses and Opportunistic Infections
(CROI 2014)
Boston, MA
March 3 - 7, 2014


7th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention
(IAS 2013)
Kuala Lumpur, Malaysia
June 30 - July 3, 2013


more conference coverage

[ about AIDSmeds | AIDSmeds advisory board | our staff | advertising policy | advertise/contact us]
© 2014 Smart + Strong. All Rights Reserved. Terms of use and Your privacy.
Smart + Strong® is a registered trademark of CDM Publishing, LLC.