iTRAQ Quantitative Proteomic Analysis of Vitreous from Patients with Retinal Detachment

Abstract

Rhegmatogenous retinal detachment (RRD) is a potentially blinding condition characterized by a physical separation between neurosensory retina and retinal pigment epithelium. Quantitative proteomics can help to understand the changes that occur at the cellular level during RRD, providing additional information about the molecular mechanisms underlying its pathogenesis. In the present study, iTRAQ labeling was combined with two-dimensional LC-ESI-MS/MS to find expression changes in the proteome of vitreous from patients with RRD when compared to control samples. A total of 150 proteins were found differentially expressed in the vitreous of patients with RRD, including 96 overexpressed and 54 underexpressed. Several overexpressed proteins, several such as glycolytic enzymes (fructose-bisphosphate aldolase A, gamma-enolase, and phosphoglycerate kinase 1), glucose transporters (GLUT-1), growth factors (metalloproteinase inhibitor 1), and serine protease inhibitors (plasminogen activator inhibitor 1) are regulated by HIF-1, which suggests that HIF-1 signaling pathway can be triggered in response to RRD. Also, the accumulation of photoreceptor proteins, including phosducin, rhodopsin, and s-arrestin, and vimentin in vitreous may indicate that photoreceptor degeneration occurs in RRD. Also, the accumulation of photoreceptor proteins, including phosducin, rhodopsin, and s-arrestin, and vimentin in vitreous may indicate that photoreceptor degeneration occurs in RRD. Nevertheless, the differentially expressed proteins found in this study suggest that different mechanisms are activated after RRD to promote the survival of retinal cells through complex cellular responses.

Molecular pathogenesis of rhegmatogenous retinal detachment

“…Previous studies have shown that the mammalian retinal function is dependent on glycolysis 30 . Indications of increased energy metabolism during RRD have been shown previously 17 , and they suggested that retinal cells try to compensate for metabolic stress by increasing energy production after RRD. However, the consequence of this is, that these glycolytic proteins are released into vitreous as the disease progresses to a more difficult condition.…”

“…Quantitative proteomics has become an indispensable method of providing molecular level information on the pathogenesis, diagnosis, and treatment of ophthalmic diseases, primarily focusing on the acellular vitreous, where protein content reflects well with the pathogenesis of the surrounding tissues 12 . Currently, the majority of proteomic studies characterizing disease‐induced vitreous proteome changes have been analyzed using data-dependent acquisition (DDA) method where selected number of peptides are sequentially selected for MS2 analysis 13 – 17 . However, the stochastic precursor selection of DDA can lead to inconsistent detection of peptides and the corresponding proteins in the sample cohort.…”

Diabetes Induced Alterations in Murine Vitreous Proteome Are Mitigated by IL-6 Trans-Signaling Inhibition

“…42 Ywhae plays a role in the cellular response to heat stress and regulation of apoptotic signaling and is known to be expressed in murine photoreceptors. 43 Two proteins downregulated in the vitreous of diabetic mice as compared to controls are major urinary protein 4 (Mup4) and 8 (Mup8). MUPs are part of the lipocalin family, which are involved in communication and regulate glucose and lipid metabolism.…”

Proteomic insight into the pathogenesis of CAPN5-vitreoretinopathy

“…AMD, age-related macular degeneration; PDR, proliferative diabetic retinopathy; PVR, proliferative vitreoretinopathy; RRD, rhegmatogenous retinal detachment. Protein CAPN5-NIV AMD PDR PVR RRD Uveitis Interleukin-6 (IL-6) Elevated 2 Elevated 51 Elevated 52 Vascular endothelial growth factor (VEGF) Elevated 2 Elevated 53 Elevated 54 Elevated 51 Platelet-derived growth factor B (PDGFB) Elevated 2 Elevated 55 Scavenger receptor cysteine-rich type 1 protein M130 (CD163) Elevated Lymphocyte cytosolic protein 1 (LCP1) Elevated Complement component C1R Elevated Elevated 31 Elevated 56 Complement component C6 Elevated Elevated 31 Complement component C7 Elevated Elevated 31 Elevated 57 Complement component C8 Elevated Elevated 57 Elevated 56 Complement component C9 Elevated Elevated 31 Elevated 57 Elevated 58 Elevated …”

“…AMD, age-related macular degeneration; PDR, proliferative diabetic retinopathy; PVR, proliferative vitreoretinopathy; RRD, rhegmatogenous retinal detachment. Pathway CAPN5-NIV AMD PDR PVR RRD Uveitis Acute phase response signaling Enriched Complement cascade Enriched Enriched 31 Enriched 57 Enriched 58 Enriched 56 Oxidative stress defense Downregulated Enriched 31 Downregulated 57 Downregulated 58 Synaptic transmission Downregulated Enriched 56 VEGF and PDGF signaling Enriched 2 Enriched 53 Enriched 54 , 55 Enriched 51 Enriched 9 mTOR and PI3K signaling Enriched 2 Enriched 51 Superscript numbers denote the corresponding references. …”