HDAC1 and Hyperglycemia: The Janus kinase (JAK)–signal transducer and activator of transcription 3 (STAT3) signalling pathway is activated by hyperglycaemia, and STAT3 phosphorylation enhances HDAC1 and downregulates autophagy markers, including P62.189 HDAC3 is highly expressed in the retina tissues of DR mice.