Proteomic Analysis of Embryonic and Young Human Vitreous

Abstract

PURPOSE. The proteomic profile of vitreous from second-trimester human embryos and young adults was characterized using mass spectrometry and analyzed for changes in protein levels that may relate to structural changes occurring during this time. This vitreous proteome was compared to previous reports to confirm proteins already identified and reveal novel ones. METHODS.Vitreous from 17 human embryos aged 14 to 20 weeks gestation (WG) and from a 12-, a 14-, a 15-, and a 28-year-old was individually analyzed using tandem mass spectrometry-based proteomics. Peptide spectral count associations with embryonic age were assessed using a general linear model of fold changes and Spearman's rank correlation. Differences between embryonic and young adult vitreous proteomes were also compared. Immunohistochemistry was used to evaluate three proteins in five additional fetal (10-18 WG) human eyes.RESULTS. There were 1217 proteins identified in fetal and young adult human vitreous, 206 after quantile normalization and variance filtering. In embryos, the peptide counts of 37 proteins changed significantly from 14 to 20 WG: 75.7% increased, 24.3% decreased. Immunohistochemistry confirmed the absence of clusterin and cadherin in 10 and 14 WG eyes and their presence at 18 WG. Comparing embryonic to young adult vitreous, 47 proteins were significantly higher or lower. A total of 768 proteins not previously identified in the literature are presented. CONCLUSIONS.Proteins previously unreported in the human vitreous were identified. The human vitreous proteome undergoes significant changes during embryogenesis and young adulthood. A number of protein levels change considerably during the second trimester, with the majority decreasing.

Diffusion and Protein Corona Formation of Lipid-Based Nanoparticles in the Vitreous Humor: Profiling and Pharmacokinetic Considerations

“… h Reported on gold and silica nanoparticles by Jo. 30 I Not previously reported in human vitreous by Semba, 26 Aretz, 27 Yee, 28 and Skeie. 29 …”

Proteomic Analysis of the Bovine and Human Ciliary Zonule

“…Recent proteomic analyses of human vitreous humor 48 – 50 have identified many hundreds of protein components, of which a core set of 231 proteins were detected in all studies. In the present study, after filtering against the matrisome database, we identified 200 components of the bovine vitreous.…”

Differential Expression of Vitreous Proteins in Young and Mature New Zealand White Rabbits

“…In addition, because of the large number of the new proteins identified in the rabbit vitreous that were not previously reported in human or rodent vitreous, it is possible that the rabbit may have a different protein profile compared to humans and rodents, therefore, caution should be taken in interpreting data from different species. It is also possible that sample preparation techniques used in this and other studies were different and may have resulted in the protein differences seen between our study and those previously published[ 18 – 21 ]. Additional comparative protein profiling of the rabbit vitreous and the vitreous protein profile of human and mouse using the same sample preparation and analysis methods might be wanted.…”

“…Other studies such as those performed by Aretz et al[ 19 ] and Murphy et al[ 20 ] identified 1111 and 1205 proteins from human vitreous respectively, the latter included proteins identified with 1 unique peptide. Recently Yee et al detected 1217 proteins in fetal and young adult human vitreous, and identified differences between embryonic and young adult vitreous proteomes[ 21 ]. In this study, we identified only 466 proteins, 299 of these are new and have not been previously reported in either of aforementioned studies excluding that by Murphy et al[ 20 ] ( Fig 1 ).…”