Aberrant expression of human endogenous retroviruses and SETDB1 in adolescents with anorexia nervosa

Human endogenous retroviruses (HERVs) represent 8% of the human genome. They are remnants of ancient infections of germinal cells. HERVs are no longer infectious, but some retroviral sequences can be activated and their enhanced expressions have been implicated in a number of diseases, including neuropsychiatric disorders. HERV transcription is regulated by TRIM28 and SETDB1, which are directly involved in the regulation of epigenetic processes, in neural cell differentiation, and brain inflammation. HERVs and TRIM28/SETDB1 expressions have not been investigated in patients affected by anorexia nervosa (AN). We assessed, through a PCR real-time Taqman amplification assay, the transcription levels of pol genes of HERV-H and -K, of env genes of Syncytin 1 (SYN1) and SYN2 as well as of TRIM28 and SETDB1 in whole blood of 37 adolescents with AN and in healthy controls (HC) of comparable age. The transcriptional levels of HERV-H-pol and HERV-K-pol as well as of SETDB1 were significantly higher in AN patients as compared with HC, while no differences were observed for SYN1, SYN2, and TRIM28. Over-expressions of HERVs and of SETDB1 in adolescents with AN suggest that they may be main actors in the pathophysiology of AN and open the way to development of novel therapeutic strategies.