From Perplexity A.I. Does inflammation cause the reactivation of endogenous retroviruses, some with pathological potential? Yes, inflammation can cause the reactivation of endogenous retroviruses (ERVs), and some of these reactivated ERVs have pathological potential. Multiple studies and reviews support a bidirectional relationship between inflammation and ERV expression: Triggering Reactivation: Inflammatory processes, including those linked to infections, oxidative stress, or microbiota alterations, can remove epigenetic blocks (like DNA methylation) that normally silence ERVs in the genome. Loss of these controls leads to an increase in ERV expression. Pathogenic Potential: Once reactivated, ERV transcripts and proteins can act as pathogen-associated molecular patterns (PAMPs), triggering the host’s innate immune response via pattern recognition receptors (PRRs) such as TLRs, cGAS, RIG-I, and MDA5. This activation not only drives further inflammation but can also contribute to ...