 |
|
MicroRNAs may be key to HIV's ability to hide, evade drugs, Jefferson scientists find
October 01, 2007(PHILADELPHIA) Tiny pieces of genetic material called microRNA (miRNA), better known for its roles in cancer, could be a key to unlocking the secrets of how HIV, the AIDS virus, evades detection, hiding in the immune system. Researchers at Jefferson Medical College in Philadelphia have shown that when an individual infected with HIV receives a powerful cocktail of antiviral agents called HAART (highly active antiretroviral therapy), the virus calls on miRNAs to help it remain quiet and practically undetectable, temporarily shutting down its ability to replicate and infect.
The work, which appears September 30, 2007 in an early online edition of the journal Nature Medicine, may also have implications for new treatment strategies against the virus. According to Hui Zhang, M.D., Ph.D., associate professor of Medicine in the Division of Infectious Diseases at Jefferson Medical College of Thomas Jefferson University, who led the work, if researchers can learn to manipulate miRNA's inhibitory effect on HIV, they might be able to devise strategies to bring the virus out of hiding, or "latency," making it vulnerable to drugs and the body's immune system.
While HAART can drive the number of HIV particles in the blood to practically undetectable levels, the virus is not eliminated. It hides in "resting" immune system CD4 T cells in the body, including the testis, brain, and other places. The drug combination has to be taken the rest of the patient's life; if halted, the virus becomes active again.
"HIV latency and how to eliminate the replication-competent - and hidden - virus are big problems," Dr. Zhang explains, noting that the molecular mechanisms that are responsible for latency are unclear.
Dr. Zhang, post-doctoral fellow Jialing Huang, Ph.D., and their colleagues may have come across one possible explanation. HIV, they have found, recruits cellular miRNA - noncoding genetic material that has been shown to play a variety of roles in cancer and in biological regulation - in resting T cells to "control the translation of viral RNA into protein." This is the last step in the creation of HIV antigens, which make the virus visible to the immune system.
The team showed that a cluster of miRNAs bind to a certain location on the viral RNA, which in turn, blocks the creation of important proteins, and HIV replication. Resting CD4 T cells, they found, are "enriched" with more than the normal amount of these miRNAs compared to the activated T cells. When the researchers used antisense technology to block miRNA-caused viral inhibition, they found that the HIV again was active and able to replicate - proving miRNA's critical role in maintaining latency.
While Dr. Zhang and his team continue to study how cellular miRNA contributes to latency, he notes that using miRNA inhibitors "might become a kind of therapeutic approach to get the virus out of hiding, making it visible and a target" for the immune system. "That's the next step," he says.
Thomas Jefferson University
"HIV latency and how to eliminate the replication-competent - and hidden - virus are big problems," Dr. Zhang explains, noting that the molecular mechanisms that are responsible for latency are unclear.
Dr. Zhang, post-doctoral fellow Jialing Huang, Ph.D., and their colleagues may have come across one possible explanation. HIV, they have found, recruits cellular miRNA - noncoding genetic material that has been shown to play a variety of roles in cancer and in biological regulation - in resting T cells to "control the translation of viral RNA into protein." This is the last step in the creation of HIV antigens, which make the virus visible to the immune system.
The team showed that a cluster of miRNAs bind to a certain location on the viral RNA, which in turn, blocks the creation of important proteins, and HIV replication. Resting CD4 T cells, they found, are "enriched" with more than the normal amount of these miRNAs compared to the activated T cells. When the researchers used antisense technology to block miRNA-caused viral inhibition, they found that the HIV again was active and able to replicate - proving miRNA's critical role in maintaining latency.
While Dr. Zhang and his team continue to study how cellular miRNA contributes to latency, he notes that using miRNA inhibitors "might become a kind of therapeutic approach to get the virus out of hiding, making it visible and a target" for the immune system. "That's the next step," he says.
Thomas Jefferson University
Immune System Current Events and Immune System News RSSResearcher tricks immune system in diabetic mice
The body's immune system hates strangers. When its security patrol spots a foreign cell, it annihilates it.
New platinum-phosphate compounds kill ovarian cancer cells
A new class of compounds called phosphaplatins can effectively kill ovarian, testicular, head and neck cancer cells with potentially less toxicity than conventional drugs, according to a new study published this week in the journal Proceedings of the National Academy of Sciences.
Landmark study defines benefits of early HIV testing and treatment for infected infants
Testing very young babies for HIV and giving antiretroviral therapy (ART) immediately to those found infected with the virus dramatically prevents illness and death, according to a report in the New England Journal of Medicine.
Stopping germs from ganging up on humans
Keeping germs from cooperating can delay the evolution of drug resistance more effectively than killing germs one by one with traditional drugs such as antibiotics, according to new research from The University of Arizona in Tucson.
JDRF funded research shows promise for prevention, reversal of type 1 diabetes
Researchers at the University of California, San Francisco have reported that two common cancer drugs have been used to block and reverse type 1 diabetes in mice.
2 new compounds show promise for eliminating breast cancer tumors
Two new compounds created by a University of Central Florida professor show early promise for destroying breast cancer tumors.
Adalimumab may reduce health-care costs for Crohn's disease patients
Inflammatory bowel disease (IBD) is a term that refers to both ulcerative colitis (UC) and Crohn's disease (CD). IBD occurs most frequently in people in their late teens and twenties. There have been cases in children as young as two years old and in older adults in their seventies and eighties; men and women have an equal chance of getting the disease.
Purdue researcher invents molecule that stops SARS
A Purdue University researcher has created a compound that prevents replication of the virus that causes SARS and could lead to a treatment for the disease.
The miseries of allergies just may help prevent some cancers, study finds
There may be a silver -- and healthy -- lining to the miserable cloud of allergy symptoms: Sneezing, coughing, tearing and itching just may help prevent cancer -- particularly colon, skin, bladder, mouth, throat, uterus and cervix, lung and gastrointestinal tract cancer, according to a new Cornell study.
Researchers aim to over-stress already taxed mantle cell lymphoma cells
Cancer cells are already stressed by the fast pace they require to grow and spread and scientists believe a little more stress just may kill them.
More Immune System Current Events and Immune System News Articles
 | The Immune System by Peter Parham The Immune System, Second Edition has been designed for use in immunology courses for undergraduate, medical, dental, and pharmacy students. This class-tested and successful textbook synthesizes the established facts of immunology into a comprehensible, coherent, and up-to-date account of how the immune system works, rather than presenting immunology as a chronology of experiments and... |
 | How the Immune System Works (Blackwell's How It Works) by Lauren M. Sompayrac Understanding the immune system is crucial for both medical and bioscience students, with new research revealing yet more secrets year on year. Many books offer in-depth introductions to the subject, but How the Immune System Works remains uniquely popular for its personable and practical overview of the nuts and bolts of the immune system.This third edition provides a perfect introduction to the... |
 | The Immune System Cure: Optimize Your Immune System in 30 Days-The Natural Way! |
 | Meditations for Enhancing Your Immune System by Bernie Siegel Resources to face your health... |
 | Boost Your Child's Immune System: A Program and Recipes for Raising Strong, Healthy Kids by Lucy Burney Ideal for all parents, whatever their children's age—how to help kids be fit and strong for life, from a top nutrition specialist. Making the most of superfoods and nutrients, this powerful guide gives parents the building blocks and a clear plan to raise kids who are fit and strong for life and capable of fighting off bugs and infections. Top nutrition specialist Lucy Burney walks parents... |
 | The Top 100 Immunity Boosters: 100 Recipes to Keep Your Immune System Fighting Fit by Charlotte Haigh Eat well today for a healthier tomorrow! With proper nutrition, we can actually bolster our immune system—and, as these 100 recipes prove, it’s not only easy to do, it’s also delicious. Here are foods rich in important vitamins, such as A, B complex, C, and E; in minerals, including zinc, selenium, and calcium; in Omega-3 and -6 fatty acids; and in protein and fiber. For each choice,... |
 | Healing HIV: How To Rebuild Your Immune System by Jon D., M.D. Kaiser, Jon D. Kaiser |
 | 90-Day Immune System Makeover by Janet C. Maccaro No matter how your health has been in the past, there is something you can do right now—a complete makeover to give you the vitality and energy to embrace life at your best! In just ninety days, Janet Maccaro will enable you to build and strengthen your immune system to bring your body into proper balance and experience disease-free living. Birthed out of Maccaro’s twenty-year struggle with... |
 | Supercharge Your Immune System: 100 Ways to Help Your Body Fight Illness - One Glass at a Time by Ellen Brown, Karen Konopelski It's now an accepted medical fact that the nutrients in certain fruits and vegetables make them "super foods" because they are the highest in the vitamins and other nutrients that naturally build our immune systems. Smoothies --frosty, thick, luscious drinks--are a way that all members of the family can gleefully boost their nutrition and maintain strong immune systems, and Supercharge Your... |
 | The Antibiotic Alternative: The Natural Guide to Fighting Infection and Maintaining a Healthy Immune System by Cindy L.A. Jones Ph.D., Linda White Avoid the dangerous overuse of antibiotics by using natural herbal remedies to strengthen your own immune defenses. • Protect yourself and your family from the misuse of antibiotics. • Learn how to control and overcome infections with natural remedies. • Maintain a vibrant and healthy immune system without antibiotic dependency. When antibiotics were discovered they were hailed as the magic... |
| © 2008 BrightSurf.com |