This is how the gene scissors work: Brec1 recombinase (yellow) triggers the HIV genome (turquoise) out of the DNA strand of a human cell. (Photo: Heinrich Pette Institute)
Reading aloud HIV infection no longer means a death sentence today. With the help of medication, the outbreak of immunodeficiency AIDS can be prevented. But to completely eradicate the virus in the body, there is no drug. The reason: The pathogen nests in the genome of infected body cells - and slumbers there until it can be active. It is exactly this behavior of the HIV virus that researchers are taking advantage of. They developed a genetic scissors that cuts out the HIV DNA from infected cells. This was already achieved by American researchers in 2014 in human cell cultures, now German scientists want to use the same method to cure patients.

Worldwide, 37 million people are infected with the HI virus, and every year, two million more people are infected with the virus. So far, infected persons could prevent the outbreak of immunodeficiency AIDS by the so-called Highly Active Antiretroviral Therapy (HAART). Drugs continuously suppress the development of virus particles. Taking those affected daily their medication, they can thereby lead a largely normal life. However, side effects of the therapy put a strain on their health and, moreover, the medicines are expensive. But researchers have been embarking on a solution for some years now, which shows promising results: completely eliminating the pathogen in the body.

This is tricky, because the virus hides skillfully: After a virus particle has penetrated into a cell, it builds its DNA permanently in their genetic material. As a result, it becomes part of human DNA. In 2014, researchers led by Kamel Khalili of the Temple University School of Medicine first succeeded in literally cutting out the genetic source of infection.

Defeat HIV with the Gen scissors

They used enzyme-nucleotide combinations that can specifically recognize and release the HIV DNA in the genome of infected cells. Subsequently, the cell's DNA repair system rejoins the loose ends and is virus-free. With this concept, the researchers have already successfully removed the pathogen from human cell cultures in the laboratory. This result was also achieved by physicians of the TU Dresden and the Heinrich Pette Institute (HPI) in Hamburg. They developed a gene scissors, the so-called Brec1 recombinase, which could free more than 90 percent of the affected human cells from the virus.

Like their American counterparts, the German researchers have programmed their gene-shears so that they only work when they encounter an HIV-infected cell - and even cut out the viral DNA. As a result, the human genome remains undamaged.

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"This is an important step on the path to developing HIV / AIDS cure, " said Kamel Khalili of the Temple University School of Medicine in 2014. The only hurdle that hindered successful therapy development to date has been ensuring that all infected cells be achieved in the body.

Study planned on patients

The researchers of the TU Dresden and the HPI in Hamburg also want to move closer to this goal. According to Berliner Morgenpost, a study with ten patients is planned for this year. "The results obtained form the basis for the first clinical studies on the healing of HIV patients, which will be carried out in Hamburg in the foreseeable future, " the newspaper quoted the physician Joachim Hauber from the HPI. To begin the study, however, the researchers still have to find investors who make available about 15 million euros.

Either way, study director Frank Buchholz from TU Dresden is certain: "Generating molecular scalpels, such as Brec1 recombinase, will change medicine, " said the physician. "Not only HIV patients will benefit from this development, but also many other patients with genetic disorders. We are about to usher in the age of genomic surgery. "

© science.de
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