HDAC1 and retinal disorder: This protective effect was attributed to the exosomes’ ability to deliver the Splicing factor proline- and glutamine-rich (SFPQ) protein to Müller cells, resulting in increased expression of histone deacetylase 1 (HDAC1); an increase in HDAC1 activity within Müller cells prompts the deacetylation and subsequent suppression of hypoxia inducible factor (HIF)-2α, a protein associated with retinal disorders and hypoxia-triggered damage.