TY - JOUR
T1 - Heterogeneous Distribution of Axonal Cytoskeleton Proteins in the Human Optic Nerve
AU - Balaratnasingam, C.
AU - Morgan, William
AU - Johnstone, V.
AU - Cringle, Stephen
AU - Yu, Dao-Yi
PY - 2009
Y1 - 2009
N2 - PURPOSE. Cytoskeleton proteins play a critical role in maintainingretinal ganglion cell structure, viability, and function. Thisstudy documents the distribution of cytoskeleton protein subunitsin the various regions of the normal human optic nerveand identifies important relationships among mitochondria,myelin, and neurofilament proteins.METHODS. Twenty-three optic nerves from human cadaverswere used. Confocal microscopy was used to examine thedistribution of neurofilament light, neurofilament medium,neurofilament heavy (phosphorylated and unphosphorylated),neurofilament heavy (phosphorylated only), actin, and microtubuleassociated protein (MAP)-1 along the sagittal plane ofthe optic nerve. Comparisons were made among superior,middle, and inferior regions and also among temporal, central,and nasal portions of the optic nerve. Colocalization of neurofilamentlight, mitochondrial cytochrome c oxidase (COX), andmyelin was also performed.RESULTS. There are significant differences in the pattern anddistribution of neurofilament protein subunits, actin, andMAP-1 along the sagittal plane of the optic nerve. Cytoskeletonproteins and COX mitochondria are found in highest concentrationsin the prelaminar and lamina cribrosa regions. COXand neurofilament light occurs predominantly in unmyelinatednerve, with a significant decrease in concentration occurringon optic nerve myelination.CONCLUSIONS. The heterogeneous distribution of cytoskeletonproteins along the sagittal plane may be an important functionaladaptation that reflects the nonuniform nature of thephysiological and structural environment of the optic nerve.The heterogeneous distribution of cytoskeleton proteins mayalso partly account for the asymmetric pattern of optic nervedamage after intraocular pressure elevation.
AB - PURPOSE. Cytoskeleton proteins play a critical role in maintainingretinal ganglion cell structure, viability, and function. Thisstudy documents the distribution of cytoskeleton protein subunitsin the various regions of the normal human optic nerveand identifies important relationships among mitochondria,myelin, and neurofilament proteins.METHODS. Twenty-three optic nerves from human cadaverswere used. Confocal microscopy was used to examine thedistribution of neurofilament light, neurofilament medium,neurofilament heavy (phosphorylated and unphosphorylated),neurofilament heavy (phosphorylated only), actin, and microtubuleassociated protein (MAP)-1 along the sagittal plane ofthe optic nerve. Comparisons were made among superior,middle, and inferior regions and also among temporal, central,and nasal portions of the optic nerve. Colocalization of neurofilamentlight, mitochondrial cytochrome c oxidase (COX), andmyelin was also performed.RESULTS. There are significant differences in the pattern anddistribution of neurofilament protein subunits, actin, andMAP-1 along the sagittal plane of the optic nerve. Cytoskeletonproteins and COX mitochondria are found in highest concentrationsin the prelaminar and lamina cribrosa regions. COXand neurofilament light occurs predominantly in unmyelinatednerve, with a significant decrease in concentration occurringon optic nerve myelination.CONCLUSIONS. The heterogeneous distribution of cytoskeletonproteins along the sagittal plane may be an important functionaladaptation that reflects the nonuniform nature of thephysiological and structural environment of the optic nerve.The heterogeneous distribution of cytoskeleton proteins mayalso partly account for the asymmetric pattern of optic nervedamage after intraocular pressure elevation.
U2 - 10.1167/iovs.08-3206
DO - 10.1167/iovs.08-3206
M3 - Article
SN - 0146-0404
VL - 50
SP - 2824
EP - 2838
JO - Investigative ophthalmology & visual science
JF - Investigative ophthalmology & visual science
IS - 6
ER -