Fig 1: Knocking down HK2 led to upregulation of enzymes in the TCA cycle.A–D Immunostaining for enzymes in the TCA cycle including pyruvate dehydrogenase E1a (PDHE1a, A and B) and oxoglutarate dehydrogenase (OGDH, C and D) in retinal sections from HKKO mice and age-matched WT controls. Loss of HK2 in rods led to increased expression of PDHE1a (A, B) and OGDH (C, D) in the photoreceptor inner segments (PIS). The panel of images in (B) and (D) are higher-power images of areas in (A) and (C) respectively. Scale bar: 50 µm in (A–D). E, F Western blots indicated that the expression of PDHE1a (C) and OGDH (D) was significantly increased in HKKO mice compared with age-matched WT controls. *p < 0.05 and **p < 0.01, n = 4/group.