Latent viruses reduce life expectancy
Telomeres are repetitive DNA sequences at the ends of chromosomes. Each cell division is accompanied by a shortening of telomeres, which limits the number of divisions. The results of many studies have shown that longer telomeres are associated with a longer human lifespan. An interesting fact is that carriers of latent (asymptomatic) viral infections have shorter telomeres. This important observation has remained a mystery to experts for a long time, and only recently have researchers been able to partially uncover the mechanisms underlying this phenomenon.
Most people are infected with latent viruses. For example, cytomegalovirus is registered in more than 60-70% of people over the age of 50. There is evidence that people with symptoms of cytomegalovirus are characterized by increased overall mortality (mortality for all reasons) compared to uninfected people.
Hanan Polansky and Adrian Javaherian from the Center for the Biology of Chronic Diseases in Valley Cottage, New York have proposed a theory explaining how latent viral infections can lead to telomere shortening. The mechanism of "micro-competition" underlying this theory is described by the example of latent cytomegalovirus infection.
One of the systems for maintaining telomere length is represented by six proteins of the shelterin family. One of these proteins, telomeric repeat binding factor–1 (Terf2), maintains telomere length by activating the enzyme telomerase. The production of this protein is triggered in response to the attachment of the transcription factor GABP to the gene encoding it. As it turned out, the cytomegalovirus embedded in the human genome also uses this transcription factor to activate its own genes, thereby depriving the cell of the opportunity to activate the Terf2 gene and, accordingly, launch the synthesis of its protein product. The result of a deficiency of this protein is a shortening of telomeres.
The theory of micro-competition proposed by the authors not only provides new targets for drugs, but also indicates the need to develop behavioral change schemes aimed at reducing the risk of the disease becoming active and increasing the life expectancy of carriers of chronic viral infections.
The article by Hanan Polansky, Adrian Javaherian The latent cytomegalovirus decreases telomere length by microcompetition is published in the open access journal Open Medicine.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on Medical News Today: Latent virus and life expectancy.07.07.2015