An in vitro model of chronic wounding and its implication for age-related macular degeneration

Abstract

Degeneration of the retinal pigment epithelium (RPE) plays a central role in age-related macular degeneration (AMD). Throughout life, RPE cells are challenged by a variety of cytotoxic stressors, some of which are cumulative with age and may ultimately contribute to drusen and lipofuscin accumulation. Stressors such as these continually damage RPE cells resulting in a state of chronic wounding. Current cell-based platforms that model a state of chronic RPE cell wounding are limited, and the RPE cellular response is not entirely understood. Here, we used the electric cell-substrate impedance sensing (ECIS) system to induce a state of acute or chronic wounding on differentiated human fetal RPE cells to analyze changes in the wound repair response. RPE cells surrounding the lesioned area employ both cell migration and proliferation to repair wounds but fail to reestablish their original cell morphology or density after repetitive wounding. Chronically wounded RPE cells develop phenotypic AMD characteristics such as loss of cuboidal morphology, enlarged size, and multinucleation. Transcriptomic analysis suggests a systemic misregulation of RPE cell functions in bystander cells, which are not directly adjacent to the wound. Genes associated with the major RPE cell functions (LRAT, MITF, RDH11) significantly downregulate after wounding, in addition to differential expression of genes associated with the cell cycle (CDK1, CDC6, CDC20), inflammation (IL-18, CCL2), and apoptosis (FAS). Interestingly, repetitive wounding resulted in prolonged misregulation of genes, including FAS, LRAT, and PEDF. The use of ECIS to induce wounding resulted in an over-representation of AMDassociated genes among those dysregulated genes, particularly genes associated with advanced AMD. This simple system provides a new model for further investigation of RPE cell wound response in AMD pathogenesis.

Application of adipose mesenchymal stem cell-derived exosomes-loaded β-chitin nanofiber hydrogel for wound healing

“…In order to further clarify the promotion mechanism of AMSC-exos-loaded β-ChNF hydrogel on wound healing, experiments in vitro and in vivo were conducted. In the absence of known targets, transcriptome and proteomics analysis can be used to study the mechanism of an intervention [29]. After the intervention of AMSC-exos-loaded β-ChNF hydrogel, we found the changes in 18 genes and 169 proteins based on transcriptome and proteomics.…”

An In Silica Model for RPE Loss Patterns in Choroideremia

“… 24 – 26 Another model to explain the tendency of RPE atrophy to occur along a border with dead cells is that RPE cell loss may be repaired if the neighboring RPE cells are healthy, where atrophy may propagate when the ability of neighboring cells to migrate and expand fails. 18 , 26 , 27 We propose this computational method may be useful in modeling other retinal degenerations, whether they be peripheral or macular diseases. Additional study is required to fully understand the pathogenesis of this important disease.…”