False-colored scanning electron micrograph of HIV particles (yellow) infecting a human H9 T cell (blue, turquoise)
In some ways, HIV resembles a minimalist painter, using a few basic components to achieve dramatic effects. The virus contains just nine genes encoding 15 proteins, which wreak havoc on the human immune system. But this bare bones approach could have a fatal flaw. Lacking robust machinery, HIV hijacks human proteins to propagate, and these might represent powerful therapeutic targets.
Using a technique called RNA interference to screen thousands of genes, Harvard Medical School researchers have now identified 273 human proteins required for HIV propagation. The vast majority had not been connected to the virus by previous studies. The work appears online in Science Express on Jan. 10.
When ancient retroviruses slipped bits of their DNA into the primate genome millions of years ago, they successfully preserved their own genetic legacy. Today an estimated 8 percent of the human genetic code consists of endogenous retroviruses (ERVs)–the DNA remnants from these so-called “selfish parasites.”
Surprisingly, the infected hosts and their primate descendants also appear to have benefited from this genetic invasion, new evidence suggests. The ancient retroviruses–distant relatives of the human immunodeficiency virus (HIV)–helped a gene called p53 become an important “master gene regulator” in primates, according to a study published this week in the online early edition of Proceedings of the National Academy of Sciences.
In this cool animation the mode of action of a novel HIV drug, a protease inhibitor, is explained. Protease inhibitors revolutionized treatment of HIV infection by enabling drug combinations with inhibitors of another HIV enzyme the reverse transcription. Thus, this made it more difficult for virus to develop multiple mutations simultaneously to escape the effects of a single drug.
Amazing chemistry and rational drug design is involved in creating these new drugs.
Human resistance to a retrovirus that infected chimpanzees and other nonhuman primates 4 million years ago ironically may be at least partially responsible for the susceptibility of humans to HIV infection today.
“This ancient virus is a battle that humans have already won. Humans are not susceptible to it and have probably been resistant throughout millennia,” said senior author Michael Emerman, Ph.D., a member of the Human Biology and Basic Sciences divisions at the Hutchinson Center. “However, we found that during primate evolution, this innate immunity to one virus may have made us more vulnerable to HIV.”
A new category of drug has shown promising results for HIV/AIDS patients who failed to respond to other treatments, a study to be shows.
Especially when combined with other medications, raltegravir — the first in a new class of anti-retroviral drugs called integrase inhibitors — dramatically reduced the presence of the HIV virus and boosted immunity in clinical-trial patients, according to the study in the British journal The Lancet.
Continue reading “New HIV drug shows ‘unprecedented’ results”
This is an outstanding 3D animation of HIV replication cycle. I especially loved the entry part, which is like watching a science fiction movie.
The animation is fairly accurate representation of what we know about the this viruses life cycle today, except the part on entry of viral DNA into nucleus. Based on our current knowledge, import of viral DNA into nucleus is not dependent on integrase but other viral and host proteins that are still elusive. Integrase is however necessary for the integration of virus DNA into host genome.
Researchers at Stanford University have added one more trick to carbon nanotubes’ repertoire of accomplishments: a way to fight the human immunodeficiency virus (HIV). Chemistry professor Hongjie Dai and his colleagues have used carbon nanotubes to transport RNA into human white blood cells that defend the body from disease, making the cells less susceptible to HIV attack.
In a paper now online in the journal Angewandte Chemie, Dai and his colleagues describe attaching RNA to carbon nanotubes, which enter T cells and deliver the RNA. When the researchers placed T cells in a solution of the carbon nanotube-RNA complex, receptor proteins on the cell surfaces went down by 80 percent. Carbon nanotubes are known to enter many different types of human cells, although researchers don’t understand exactly how they do it. Some experts suspect that because of their long, thin shape, nanotubes enter cells much as a needle passes through skin.
Read rest of the story on Technology Review site
Scientists have finally deciphered the genome of the parasite causing trichomoniasis, a feat that is already providing new approaches to improve the diagnosis and treatment of this sexually transmitted disease. According to the World Health Organization trichomoniasis affects an estimated 170 million people a year and is an under-diagnosed global health problem.
Led by Jane Carlton, Ph.D., an Associate Professor in the Department of Medical Parasitology at New York University School of Medicine, the team of scientists took four years to crack the surprisingly large genome of the single-celled parasite Trichomonas vaginalis. They published the draft sequence of the parasite’s genome in the Jan. 12, 2007, issue of the journal Science.
In order to find out how one of the world’s most devastating diseases overcomes state-of-the-art drugs, scientists led by Dr. Vineet KewalRamani at National Cancer Institute (NCI) are biohacking and re-engineering the HIV virus. Dr. KewalRamani and his collegues have combined pieces of HIV and another virus to create a deadly new hybrid—a tenacious little microbe that knows all the tricks of its parent pathogens. Discovering where, and how, HIV hides in the body will be a critical step towards a cure for the disease—or at least a better treatment.
Researchers from the UCLA AIDS Institute and the Institute for Stem Cell Biology and Medicine have demonstrated for the first time that human embryonic stem cells can be genetically manipulated and coaxed to develop into mature T-cells, raising hopes for a gene therapy to combat AIDS.
The study, to be published the week of July 3 in the online edition of the Proceedings of the National Academy of Sciences, found that it is possible to convert human embryonic stem cells into blood-forming stem cells that in turn can differentiate into the helper T-cells that HIV specifically targets. T-cells are one of the body’s main defenses against disease.
Continue reading “Researchers develop T-cells from human embryonic stem cells”
The virulence characteristic of HIV-1–the virus predominantly responsible for human AIDS–might amount to an accident of evolution, new evidence reveals. A gene function lost during the course of viral evolution predisposed HIV-1 to spur the fatal immune system failures that are the hallmarks of AIDS, researchers report in the June 16, 2006 Cell.
New insights into how a subpopulation of helper T-cells provides immunity and promotes survival following infection with an AIDS-like virus offer a new means of predicting an AIDS vaccine's effectiveness, a discovery that could help scientists as they test these vaccines in clinical trials.
As the world marks the 25th year since the first diagnosed case of AIDS, groundbreaking research by scientists at Florida State University has produced remarkable three-dimensional images of the virus and the protein spikes on its surface that allow it to bind and fuse with human immune cells.
Findings from this AIDS research could boost the development of vaccines that will thwart infection by targeting and crippling the sticky HIV-1 spike proteins.