Proteomic analysis of corneal endothelial cell-descemet membrane tissues reveals influence of insulin dependence and disease severity in type 2 diabetes mellitus

Abstract

The objective of this study was to characterize the proteome of the corneal endothelial cell layer and its basement membrane (Descemet membrane) in humans with various severities of type II diabetes mellitus compared to controls, and identify differentially expressed proteins across a range of diabetic disease severities that may influence corneal endothelial cell health. Endothelium-Descemet membrane complex tissues were peeled from transplant suitable donor corneas. Protein fractions were isolated from each sample and subjected to multidimensional liquid chromatography and tandem mass spectrometry. Peptide spectra were matched to the human proteome, assigned gene ontology, and grouped into protein signaling pathways unique to each of the disease states. We identified an average of 12,472 unique proteins in each of the endothelium-Descemet membrane complex tissue samples. There were 2,409 differentially expressed protein isoforms that included previously known risk factors for type II diabetes mellitus related to metabolic processes, oxidative stress, and inflammation. Gene ontology analysis demonstrated that diabetes progression has many protein footprints related to metabolic processes, binding, and catalysis. The most represented pathways involved in diabetes progression included mitochondrial dysfunction, cell-cell junction structure, and protein synthesis regulation. This proteomic dataset identifies novel corneal endothelial cell and Descemet membrane protein expression in various stages of diabetic disease. These findings give insight into the mechanisms involved in diabetes progression relevant to the corneal endothelium and its basement membrane, prioritize new pathways for therapeutic targeting, and provide insight into potential biomarkers for determining the health of this tissue.

Donor, Recipient, and Operative Factors Associated with Graft Success in the Cornea Preservation Time Study

“…In this pre-specified secondary analysis from CPTS, we found a greater risk of graft failure with donors with a history of diabetes, and notably a rate of primary/early graft failure more than twice as high as that associated with donors without a history of diabetes (p=0.008; Table 2). Our finding with the CPTS data was not surprising, given animal and human literature reporting that the corneal endothelium is adversely affected biochemically, 27-29 morphologically, 30-32 functionally 30,31,33-35 , and with tissue damage with Descemet membrane endothelial keratoplasty (DMEK) membrane peeling 36-38 in diabetes. More recently, human corneal endothelial mitochondria 39 and Descemet membrane strength 40 have also been reported to be altered in diabetes.…”

Three kinds of corneal host cells contribute differently to corneal neovascularization

“…Although various corneal proteomes have been previously identified [40][41][42][43], to the best of our knowledge, this study is the first to report on the proteome of vascularized corneas.…”

An Update on Corneal Biomechanics and Architecture in Diabetes

“…Aldrich et al [146] report that endothelial cells from insulin-dependent diabetes patients with medical complications had variations in their mitochondrial configuration, notable Golgi bodies associated with numerous vesicles, collection of lysosomal bodies/autophagosomes, and focal production of abnormal long-spacing collagen. Skeie et al [149] found a decrease in mitochondrial proteins in corneas taken from patients with insulin-dependent diabetes when compared to those from patients with non-insulin-dependent diabetes. They suggest that proteins implicated in mitochondrial dysfunction decrease to a greater extent as diabetes progresses to insulin dependence, indicating that mitochondrial changes may be linked to diabetes insulin therapy itself or disease conditions at the time of transition to insulin therapy.…”