Journal Club - How Commonly Does Herpes Activate

Till date there are eight different herpes viruses are known in humans. They all settle down permanently in the body after acute infection. Under certain circumstances, they wake up from this dormant phase, multiply and attack other cells. This reactivation is often associated with symptoms, such as itchy cold sores or shingles.

In the course of evolution, most herpesviruses have learned to use small RNA molecules, so-called microRNAs, to reprogram their host cells to their advantage. A research team from Germany, has now been able to show for the first time that a viral microRNA acts as a master regulator to induce the reactivation of the virus. In the journal Nature, the researchers present the previously unknown cellular mechanism by which human herpes virus 6 (HHV-6) triggers its own awakening.

More than 90 percent of all people are infected with HHV-6 without noticing it. The virus probably only causes problems when it wakes up repeatedly. HHV-6 reactivation is suspected of impairing heart function, causing the rejection of transplanted organs and triggering diseases such as multiple sclerosis or chronic fatigue syndrome. In addition, recent studies suggest that this herpes virus may be involved in the development of schizophrenia, bipolar disorder and other diseases of the nervous system.

Research group was also able to show that the viral microRNA is not only essential for virus replication, but also directly triggers the reactivation of the virus from its dormant state. For the first time, this shows that a microRNA can directly regulate the maturation process of other microRNAs. Hence, the researchers concluded that artificial small RNAs can be designed to specifically switch off individual members of microRNA families.