Fig. 3

Labelling of NAD salvage pathway machinery in human retina. A NAMPT labelling is detected across all retinal layers, localizing to both nuclear (haematoxylin + ve) and cytoplasmic (haematoxylin −ve) cellular compartments, with the most intense labeling in the INL (n = 11 eyes). B NMNAT1 labelling is strongest in nuclear layers (GCL, INL, ONL) localizing to nuclei (n = 11 eyes). C NMNAT2 labelling localized to cytoplasmic compartments and was detected across all retinal layers, with the greatest intensity in the GCL, reflecting high expression in RGCs (n = 11 eyes). D In the ONH, NAMPT followed the same trend as in the retina, with labelling localizing to both nuclear and cytoplasmic compartments. Labeling intensity did not vary along the length of the optic nerve (n = 11 eyes). E NMNAT1 again localized only to nuclei in the ONH (glial framework), and its intensity was consistent along the length of the optic nerve (n = 10 eyes). F NMNAT2 conversely, localized only to the axonal compartments of the optic nerve and was significantly greater in the first 500 µm of the ONH (n = 8 eyes), potentially reflecting the density of axons relative to glial framework here, or the need for more NMNAT2 at a critical metabolic portion of the axons. N.B. these data do not allow for direct comparison of abundances of these enzymes given the nature of antibody labelling (efficiency and concentration of the antibodies etc.). RNFL retinal nerve fiber layer, GCL ganglion cell layer, IPL inner plexiform layer, INL inner nuclear layer, OPL outer plexiform layer, ONL outer nuclear layer, PS photoreceptor segments. Scale bars = 50 µm in A–C, 500 µm in D–E (overview images) and 50 µm in D–E (inset images)