Ago2, the only member with catalytic activity in the Argonaute family, is a key component of the RNA-induced silencing complex. It contains four functional core domains (N, PAZ, MID, and PIWI from N-to C-terminal) and is involved in multiple processes. It plays a crucial role in small RNAs guided post-transcriptional gene silencing, such as mRNA degradation and translational repression. Additionally, Ago2 is implicated in gene regulation in nuclei, including chromatin remodeling, transcriptional regulation, double-strand break repair, and alternative splicing. It also participates in other cellular processes like alternative polyadenylation, translational activation, and transposon repression [3].

Deletion of YTHDF1, a m6A reader protein, leads to changes in Ago2-related functions. YTHDF1 interacts with Ago2 through its YTH domain, and their co-localization in P-body is observed. YTHDF1 promotes mRNA degradation by recruiting Ago2 and facilitating P-body formation via liquid-liquid phase separation. The deletion of YTHDF1 causes P-bodies to change from liquid to gel/solid droplets, resulting in Ago2/RNA patches and mRNA degradation delay, revealing a new aspect of mRNA post-transcriptional regulation [1]. In failing hearts, nuclear Ago2, rather than cytosolic Ago2, overexpression exacerbates cardiac dysfunction. Nuclear Ago2 activates the transcription of ANKRD1, which is involved in cardiac remodeling. Drugs like ivermectin and ANPep can prevent ANKRD1 nuclear import and improve cardiac performance [2].

In summary, Ago2 is essential for post-transcriptional gene silencing and various gene-regulatory processes. Studies using gene-knockout models, like the YTHDF1-KO cell lines and overexpression models in the heart, have revealed its role in mRNA regulation and cardiac remodeling. These findings contribute to our understanding of Ago2's function in normal biological processes and disease conditions such as heart failure and potentially provide new therapeutic targets.