A Possible Role of Acrolein in Diabetic Retinopathy: Involvement of a VEGF/TGFβ Signaling Pathway of the Retinal Pigment Epithelium in Hyperglycemia

Abstract

Purpose Acrolein has been implicated in retinal pigment epithelium (RPE) cell death, and has been associated with diabetic retinopathy. Our purpose was to investigate the potential effect of high glucose in influencing acrolein-mediated RPE cytokine production and cell death. We investigated the influence of the acrolein effect on ARPE-19 cells in high glucose conditions and quantified the release of transforming growth factor β (TGFβ1 and 2) and vascular endothelial growth factor (VEGF). We assessed the ability of N-benzylhydroxylamine(NBHA) as well as TGFβ pathway inhibitors SIS3 and SB431542 to prevent this effect of acrolein on ARPE-19 cells. Materials and methods Confluent ARPE-19 cells were treated with acrolein and/or NBHA in both 5.5 and 18.8 mM glucose conditions. Cells were also pretreated with SIS3, a specific inhibitor of the SMAD3 pathway, and SB431542, a specific inhibitor of TGFβ signaling pathway, before treating them with acrolein. Viable cells were counted and ELISAs were performed to measure the cytokines TGFβ1 and 2, and VEGF released into the conditioned media. Results In ARPE-19 cells exposed to acrolein and hyperglycemia there was reduced cell viability and an increase in the cell media of VEGF, TGFβ1, and TGFβ2, which was reversed by NBHA. Acrolein/hyperglycemia-induced cell viability reduction and cytokine overproduction was also reduced by TGFβ pathway blockade. Conclusions We conclude that the effect of acrolein on the reduction of viability and VEGF increase by ARPE-19 cells in hyperglycemic media is conducted through the TGFβ signaling pathway. Our results suggest that benefits of sequestering acrolein by NBHA and the blockage of the TGFβ pathway by SB431542 and SIS3 offer suggestions as to potential useful pharmacological drug candidates for the prevention of diabetes-induced complications in the eye.

Involvement of HMGB1 mediated signalling pathway in diabetic retinopathy: evidence from type 2 diabetic rats and ARPE-19 cells under diabetic condition

“…The studies of Grigsby et al 20 also confirmed that VEGF secretion from ARPE-19 cells was associated with DR. Consistent with this, our results determined that NF-κB activity was strengthened in the retinas of type 2 diabetic rats and in ARPE-19 cells with high glucose stimulation.…”

Elevated Protein Carbonylation, and Misfolding in Sciatic Nerve from db/db and Sod1−/− Mice: Plausible Link between Oxidative Stress and Demyelination

“…Among the various oxidative modifications of proteins, carbonylation is a critical and irreparable modification that has been shown to be elevated during aging, diabetes and in neurodegeneration [12], [13], [14], [15], [16], [17], [18]. Diabetic subjects are known to have elevated glucose-, and lipoxidation-derived carbonyl stress [18], [19], [20], [21], [22], [23], however, it remains unknown if carbonylation of sciatic nerve/myelin proteins are elevated in peripheral neuropathies. Therefore, we asked (i) does oxidative stress have an effect on carbonylation and misfolding of sciatic nerve proteins in peripheral neuropathy, and (ii) is the carbonylation of sciatic nerve/myelin proteins associated with loss in nerve conduction and myelin in peripheral neuropathy?…”

Prorenin receptor (PRR)-mediated NADPH oxidase (Nox) signaling regulates VEGF synthesis under hyperglycemic condition in ARPE-19 cells

“…Incubation of ARPE-19 cells in high glucose (HG) increases the expression of VEGF [27,28]. Several enzymes including NADPH oxidase are known to generate low levels of ROS [6,29].…”