Kinesin Family Member Gene Expression Within Human RPE: Evidence That C1 Member Is Upregulated With Human Bruch’s Membrane Aging

Abstract

Abstract: : Purpose: Kinesins represent a family of microtubule–based motor proteins implicated in motile processes of neural retina and RPE cells. We have determined the expression levels of members of the kinesin superfamily genes within spontaneously immortalized RPE (ARPE19) and the effects of Bruch’s membrane aging on expression of these motor proteins. Methods: ARPE–19 cells were seeded onto human Bruch’s membrane from younger (<age 50) and older (>age 70) donors. RPE were harvested 72 hours later and total RNA was isolated using standard techniques. The RPE gene expression profile was determined using the Affymetrix Human 95UA gene chip; we calculated the ratio of expression (old/young) on old vs. young Bruch’s membrane for each gene. Data were analyzed with DNA microarray analysis software. Results: The Affymetrix chip contains a total of 43 genes within the kinesin superfamily; we were able to detect the expression of 19 of these genes in ahRPE and 23 genes within ARPE19, with 12 of them expressed in both ahRPE and ARPE19. Bruch’s membrane aging upregulates kinesin family member C1 (KIFC1) in ARPE19 (old/young = 1.6; p= 0.007) and downregulates kinesin family member 5C (KIF5C) (old/young = 0.7; p= 0.01). Conclusions: At least 19 members of the kinesin gene superfamily are expressed within human RPE, which presumably act as intracellular transport proteins carrying different cellular organelles along the microtubules. KIF1C and KIF5C have been reported to play a role during different morphogenic processes. Further work is needed to elucidate the effects of alterations in kinesin family member genes on the cell biology of the RPE and adjacent tissues.

Keywords: Bruch's membrane • aging • retinal pigment epithelium