PARP1 and diabetes mellitus: The major findings were as follows: 1) expression of caspase-14 in the retina and various retinal cells, including retinal ECs, PCs, ACs, ChECs, and RPE and TM cells; 2) upregulation and activation of caspase-14 in the human and mouse retina during diabetes; 3) increased caspase-14 expression in retinal ECs and PCs cultured under high glucose conditions; and 4) an increased number of TUNEL-positive cells and levels of apoptotic markers, cleaved PARP-1 and caspase-3, in caspase-14 expressing retinal ECs and PCs.